Multiple Units (EMU/DMU) and Other Self-propelled VehiclesOn this page
- Multiple Units
- Electric Multiple Units
- Diesel Multiple Units
- Mumbai Area EMU Numbering
- Railcars & Railbuses
- Other Self-propelled Vehicles
Q. What does the term “multiple unit” or “MU” mean, and what is an EMU or DMU?
There are two senses of the phrase “multiple unit” to be distinguished. Two or more regular locomotives may be coupled together for greater hauling capacity. In such a cases the locos are said to be operating as multiple units, or to be “MU'ed together” (US terminology: “lash-up”).
This is not to be confused with the terms electric multiple unit (EMU) or diesel multiple unit (DMU) which refer to cars used for (mostly suburban) train services which have multiple prime movers (either electric motors or diesel engines) for each car. i.e., the same car that carries passengers also has the motive power, as opposed to the normal situation where the passengers are in coaches that are not self-propelling and a locomotive hauls the train.
Electric Multiple Units
Q. What kinds of electric multiple units does IR operate?
Note: For information on the suburban/metro systems in different cities, please see the metro section. This section is concerned specifically with the features of the EMU/DMU cars used on such systems.
IR has electric multiple units in operation in several suburban and extended suburban sections (Mumbai, Delhi, Chennai, Kolkata, Hyderabad, Pune etc.). All now work using 25kV AC, although in the past the Mumbai region had EMUs that operated under 1.5kV DC. Until 2004, the Chennai area had MG EMUs.
The vast majority of EMUs, other than in the Mumbai region (see below), have DC traction motors driven by the 25kV AC system. Power is fed through the main transformer, stepped down and converted to DC voltage through silicon rectifiers. Speed control is through tap changers.
EMUs using all AC, 3-phase induction motors and IGBT-based controls similar to the ones used in Mumbai are starting to roll out to other cities.
Most suburban systems (Mumbai is an exception, see below) operate with a formation of 9 or 12 cars with 3 or 4 driving motor coaches and corresponding trailer coaches. Four basic units (two ‘End basic units’ & two ‘Middle basic units’) make a 12 car rake. Each ‘end basic unit’ comprises one driving motor coach and two trailer coaches labeled ‘C & ‘D’ type. The ‘middle basic unit’ comprises of a non-driving motor coach & two trailer coaches of ‘C & ‘D’ type.
25kV AC EMUs have classifications WAU-1 through WAU-4 (and beyond?). DC EMUs were classified WCU-1 through WCC-15. MG units were classified as YAU. (Precise information on differences among these is lacking.)
EMUs coaches are manufactured primarily by ICF, Perambur. Jessop & Co., BEML (Bharath Earth Movers Limited), Titagarh Wagons Limited are also suppliers. The later is the first private manufacturer to do so for IR. (03/2021) The newly opened Marathwada Coach Factory in Latur is expected to be the primary supplier of EMU/MEMU coaches in the coming years.
Traction and electrical equipment for EMUs is supplied by BHEL, Bombardier, Medha and Siemens.
ICF originally began building trailer coaches in 1962 and motor coaches in 1963. Initially, ICF classified these as 'AC EMU B' for motor coaches, 'AC EMU C' for trailer coaches, and 'AC EMU D' for trailer coachs with vendor compartments. There were also a variant trailer coach class 'AC EMU A' but this was merged with the 'D' class later.
BEML coaches have a lower height as they comply with the old IRS standards (like the old ICF coaches), older bogies (although many of the surviving ones have been retrofitted with Flexicoil bogies), and a tapered body profile at each end.
Regular BG EMUs are somewhat wider (12') than usual (WAG-5 is 10'8", by comparison). Hence they cannot be used in many places where the clearances are not sufficient. The coach weights range from 118t to 130t, though the newer ones with stainless steel shells weigh around 112t.
Mumbai Region EMUs
Mumbai region EMUs over CR and WR initially ran 1.5kV DC traction. But with the gradual conversion of the area to 25kV AC being planned, WR began by retrofitting around 120 DC units with Alstom 3-phase AC traction motors with GTO based control. The first such rake was commissioned on 12th June 2001 (rake number 925C-926C). In parallel, ICF began manufacturing newer AC-DC rakes powered by BHEL-Strukton. These also used 3-phase AC TM’s with GTO control. The first such rake was rolled out on 9th September 2001 and numbered 301C-302C.
Both these rakes were home at the Kandivali car shed. However, these could not be coupled together because of the differences in the electrical cable connections.
CR began running AC-DC EMUs in 2006 when some rakes were transferred from WR to enable the conversion of Asangaon - Kasara - Igatpuri to 25kv AC.
For a detailed timeline of the history and current status, please see below.
All the AC-DC coaches had provision for regenerative braking. The 9xx series rakes failed over to electro-pneumatic braking directly if regenerative braking does not work, while the 3xx series rakes failed over to dynamic (rheostatic) brakes first before failing over to the electro-pneumatic brakes. MRVC rakes (see below) fail over to electro-pneumatic brakes when regeneration is not possible.
During this time, some variations of the standard designs started appearing in the region, including some stainless steel rakes (one ordered by MRVC/WR for field trials in 2004). The stainless steel shells were developed to avoid the problem of corrosion in the coastal climate of Mumbai. Known as the 'Tanaka' design, these shells designed and developed by ICF had a straight sidewall, a simplified design of the sole bar to eliminate places prone to corrosion and to make it easier to inspect and paint. The steel used was a ferritic stainless steel (AISI 409M) in the sole bar, body pillar components, and in the side wall up to a height of 600mm. The trough floor used an austenitic stainless steel (AISI 301). Apart from the corrosion-resistance features, these EMU coaches also sported somewhat larger windows than the normal EMU coaches.
Some of these variations (the sidewall and the sole bar for e.g) have become standard over the years and are now in use for all EMU coaches. In 2009 Titagarh Wagons and Jessop started production of newer models with stainless steel bodies.
There were other one-off experiments such as a stainless-steel driving trailer at Mahalaxmi that could be coupled with 3xx series EMU rakes. A Millennium Rake was introduced on Oct. 17, 2005, with enhancements such as forced ventilation with 32 fans instead of the normal 24, and audio-visual indications in the coaches of the current location, next station, platform direction, etc. (using GPS technology).
(03/2021) EMUs in the region are a mix of the older AC-DC units and brand new all AC systems with IGBT control. The AC-DC units feature electricals from Siemens while the all AC ones have equipment from Bombardier and Medha. Western Railway now also runs air-conditioned EMUs on the Churchgate - Virar sector. These units are manufactured by ICF and feature IGBT controlled traction motors from BHEL and Medha.
The Mumbai Railway Vikas Corporation Limited (MRVC) was started in 1999 to execute urban infrastructure works under the Mumbai Urban Transport Project (MUTP). Upgraded rakes began first appearing in 2007 manufactured by ICF. These rakes have some new features like forced ventilation, better lighting, smoother ride quality because of the secondary air suspension, LED displays and announcements inside coaches to indicate the next station, stainless steel interiors (although the shells are not stainless steel), and better acceleration and braking.
Initial propulsion systems were Siemens AC-DC, but the later ones are full AC from Bombardier, Medha and BHEL. All MRVC rakes use IGBT technology for control. The brake systems include electro-pneumatic and regenerative braking; the rakes fail over to EP brakes when regeneration is not possible. A few MRVC coaches have been fitted with conical springs in their primary suspension and are cleared to run at 105km/h.
Early MRVC rakes suffered from large scale bearing failures in traction motors, which led to delays as the rakes were left stranded on line. Siemens rectified the defect under warranty.
Under phase one of the MUTP, 133 rakes with equipment from Siemens were procured. They were manufactured in a mix of 9-coach and 12-coach configurations. Both CR and WR subsequently modified the formations, converting some driving coaches to non-driving and reassembling a few into 15-coach formations.
A 9-coach rake (1181-1183) of WR had a new bolsterless bogie design which promised higher speeds and better ride quality. However, these bogies failed in trials and the entire rake was mothballed from 2011 to 2019, when the Mahalaxmi Workshops replaced the bolsterless bogies with regular ones.
Under phase 2 of the MUTP, 72 12-car rakes with propulsion equipment from Bombardier were procured. All of them were initially were to be dispatched to WR, when in late 2017/early 2018, 9 of them were sent to CR.
(03/2021) Post MUTP (although this is sometimes called phase-3), WR has received 30 rakes (with a mix of Bombardier and Medha propulsions) and CR has received 25.
MEMUs (Main-line EMUs) were introduced in 1993 to address the growing requirement for running more EMU type services on mainlines connecting urban and semi-urban clusters. All MEMUs run on 25kV AC power. MEMU driving motor coaches seat 76 and the trailer coaches seat 108. They have a top rated speed of 105km/h and are equipped with electro-pneumatic brakes.
Since 2018, newer MEMUs from ICF feature all AC propulsion systems with 3-phase traction motors (from Medha and Bombardier) and IGBT based control. These units have a top rated speed of 130km/h, though they are not run at those speeds anywhere. These units also feature upgraded interiors (similar to the ones in the MRVC rakes, though there is no forced ventilation), larger windows and an improved secondary suspension.
Earlier versions of MEMUs had a top speed of 60km/h. RDSO improved on these by increasing the horsepower of the traction motors and providing a weak-field arrangement in them for higher speeds.
RDSO Trials with Weak Field arrangement
During Dec. 13-21, 2003, RDSO carried out a series of trials with MEMU rakes carrying 'Dense Crush Loads' ('DCL') stopping at all stations on the Tundla-Kanpur section of NCR. These 4-car MEMUs were provided with a weak-field arrangement. It was seen that the use of the weak field allowed increased acceleration above 40km/h, saving time at 7% at a max. speed of 90km/h and 105 at 100km/h on the 228km stretch.
Q. What's the history of EMU services on IR?
Mumbai area EMUs date back to the 1920's. In 1925, EMUs from Cammell-Laird and Uerdingenwagonfabrik (Germany) were used on the line from Victoria Terminus to Kurla (what would become the core of the CR suburban service). In 1928, EMU rakes from Cammell-Laird/BTH were used on what is now WR. These were in use until 1974. The BTH rakes were even wider than the current 12' wide EMUs. A few Hitachi and Nippon SSK EMUs were used by what is now CR (some were acquired in 1925). These early EMUs were all vacuum-braked. (CR's EMU's had very weak horns operated by the vacuum of the brake system; WR had louder horns run by the air pressure of the pantograph reservoir.)
Birmingham Railway Carriage and Wagon Co. supplied 24 trailer cars for WR, and 32 for CR in the early 1950s. These were air-braked. In December 1947, CR ordered 56 (?) EMUs from Metroplitan Cammell, and others from Hitachi, Breda, etc. WR acquired 12 EMUs from Metropolitan Cammell. These coaches were in use until the early 1980s. Met-Cam also supplied 18 EMU coach shells, underframes, and bogies in 1955. In the 1960s EMUs from Jessop, MAN, ICF, etc. were brought into service. Later EMUs were almost all from ICF (a few from Jessop), with traction equipment from BHEL.
CR rakes (1925 stock), especially the ones run on the Harbour Branch, were generally narrower than the WR rakes, usually at 10'8" because of smaller clearances on the Harbour Branch and the need to use the Bombay EMUs for the Race Specials to Pune on the mainline until the 1930s. They were also somewhat heavier than WR EMUs. These were withdrawn around 1966.
Some EMUs from SIG (SIG-Fiat joint venture?) were run in the 1950s but they had rather different operational procedures for isolating defective motors, etc. and were withdrawn from service in the 1960s.
ICF manufactured rakes with BHEL equipment were the most common until the early 2000s when the area began conversion from 1.5kV DC to 25kV AC. Since then, AC-DC units from Siemens followed by all AC units from BHEL, Bombardier and Medha are in use. (03/2021) The initial lot of AC-DC units have almost all been withdrawn save for a few rakes for use on CR’s Trans-Harbour lines. These 6 rakes based out of the Sanpada car shed have been retrofitted with conventional DC traction motors due to reliability issues with the older AC motors.
Early Calcutta area EMUs were from ICF as were the later MG ones used in Chennai until 2004. Early MG units running on the Madras-Tambaram line were 3-car rigid units from Metro Cammell. The ICF-built MG EMUs in the Chennai system were notable for their brisk acceleration and crisp braking (they were equipped with vacuum brakes). They were also different from the EMUs in Mumbai and other places as they had a right-hand side seating position for the motorman. In the layout of controls, the master controller was on the left and the brake controller on the right.
In 1981, IR contracted with the Bhabha Atomic Research Centre (BARC) to develop energy-efficient control systems for the Mumbai EMUs. The BARC design included chopper (thyristor) control of the motor power supply instead of rheostatic control, thereby eliminating the waste of power in the resistance grids. The EMUs were also provided with the capability for regenerative braking to convert the kinetic energy of the rake back to electrical energy fed to the catenary when braking.
CR proposed inducting 6 such rakes with the improved design on a trial basis, at a cost of Rs 4.7 crore. ECIL, in conjunction with BARC, began supplying the chopper control equipment in 1992. The first chopper rakes were introduced in 1993. By 1994, 5 such 'chopper rakes' (as they are known) were brought into service. (Equipment for a sixth rake was never finished.) Serial production was never taken up as the AC-DC EMUs for the Mumbai area were anticipated to come into use shortly.
There was also a controversy regarding the actual savings that the new design yielded. BARC claimed a savings of 25% in energy consumption (18% from elimination of rheostatic control and 7% from regenerative braking). However, CR never installed monitoring equipment to measure the energy consumption in actual use which led to a complaint from the Comptroller and Auditor General.
The 9-car chopper rakes were based at Kurla. By July 2002 only two or three of the motor coaches with chopper control were ever seen. The chopper motor coaches made a characteristic humming or whining noise when beginning to accelerate, different from the standard Mumbai EMUs at the time. Serial numbers of the chopper rakes' motor coaches as seen in July 2002 were: 70537, 70528, 70523, 70536, 70531.
Q. In what formations do EMU's run?
The most common formations are 9-car and 12-car units. WR and CR in Mumbai run 15-car units during peak and designated hours.
In the 1930's, Madras suburban service started with 3-car EMUs which were notable in having coupled bogies across cars, thereby making the entire 3-car formation a rigid unit. Later Madras also got some 4-car (non-rigid) EMUs. They were sometimes operated in pairs at rush hours, leading to 6-car (two rigid) and 8-car (two non-rigid) formations, and rarely 7-car formations (one 3-car rigid and one 4-car).
In the 1960's Madras received a couple of 2-car EMUs. Following the conversion of the traction from DC to AC, the 3-car EMUs (which were built for DC) were coupled with a single AC power car to make hybrid 4-car formations.
10-car formations were seen rarely (two 3-car rigid EMUs with a 4-car EMU) in Madras. While the MRTS runs with 9-car EMUs, from 2001 until about 2006, 3-car units were run to improve frequency and turn around times. These had two power cars (driving power car at one end, and trailing power car at the other end), unusual for such short trains.
New Delhi and Hyderabad in the past had seen 6-car and 8-car EMUs, but now 9 and 12-car formations are more common.
In Mumbai, 9-car formations were standard for a long time (from 1963). (Much earlier, 4-car rakes were in use, with 8-car rakes having started on the main line from 1927.) Then in 1988 the 12-car formation became common (having been used on a trial basis from 1986), following increased demand for services and lengthening of platforms. Rumours of 15-car rakes for Dadar - Virar began around 1999, but trials began only in early 2009, with a formal commissioning in November 2009. Later, these were extended to Churchgate in January 2011. CR introduced 15-car rakes in 2013.
In all these formations, the basic unit consists of 3 cars coupled together: a driving trailer ("C"), a motorcoach or power car ("B"), and a trailer coach ("A"). The 9-car rake therefore looks like this: YSYL - YSZZ - YSFS - YSYL - YSZZ - YSFS - YSFS - YSZZ - YSYL. (YSYL = trailer coach with vendor's compartment, YSYL = driving trailer coach, YSZZ = motor coach). In the late 1960s, WR introduced a "standees" train with far fewer seats. In this rake (#701-702), one of the unused driving trailer in the middle was replaced by a power car. This 9 coach rake therefore had four power cars. In July 2006, the standee train was changed to run with only 3 power cars. By late 2010, this standee train seemed to have been withdrawn.
1950s stock EMUs from various suppliers had two units of 4 coaches each: 2 driving motor cars (power cars) and two trailer coaches sandwiched between them, so that an 8-car EMU rake had 4 power cars. While these 8-car rakes were used on the main line, 4-car rakes were used on the Harbour line, from about 1927. These 4-car units were dropped later as they put too high a load on the OHE power supply, and all 8-car rakes were converted to 9-car rakes by 1963. On the Kalyan-Kasara/Karjat sections the 4-car rakes were converted to 6-car rakes in 1964.
Over SER, services with 12-car rakes began in April 2001 replacing some of the 10-car rakes used earlier. The 12-car rakes have power cars in the first, fourth, ninth, and twelfth positions. Historically, Sealdah Main section ran mostly 9-car rakes and Sealdah South used 10-car rakes.
For a long time, over both ER and SER in the Calcutta area, AC EMU rakes were made up of 4-car units, consisting of a driving trailer ("A"), a power car ("B"), a trailer ("C") and a driving trailer ("D").
Q. What classes of accommodation do EMUs offer?
The most commonly seen coaches have General Second Class accommodation. First Class accommodation is also available widely, though not in the Delhi and Calcutta areas EMUs. First Class accommodations are also not available on MEMUs throughout IR.
There are also compartments, coaches, or entire trains reserved for women, known as Ladies' Compartments or Ladies' Specials. In some cases the Ladies' coaches or compartments are reserved for women all the time, whereas in some cases they revert to being General Second Class accommodation while being reserved for women only during certain hours. In the Mumbai area, there are also First Class coaches reserved only for women on all rakes. Until 2010, these were only available on certain services. In the Chennai area, certain seating bays in First Class sections are reserved for women.
Additionally, compartments are reserved for physically challenged persons and there are mixed compartments or sections of coaches reserved for luggage and vendors carrying large pieces of equipment.
Diesel Multiple Units
Q. Does IR operate diesel-electric or diesel-hydraulic multiple units of any kind?
There are several diesel-electric multiple units (DEMUs) and diesel-hydraulic multiple units (DHMUs) in operation. Almost all are made by ICF.
In 1993-94, the first versions of the BG DEMUs featured a Cummins VTA 1710 V-12 prime mover of 705 HP. Later versions (and still produced) starting in 1999 feature a 1400hp V-16 engine (Cummins KV-16). These are called HPDMU (High Horsepower DMU). In 2001, ICF also produced a few DEMUs featuring two underslung Cummins NT 855R engines each driving a traction alternator whose output is fed to 4 traction motors.
The HPDMUs are coupled in 4-car units (one power car + three trailer cars) as opposed to the 3-car rakes (power car + two trailer cars) for the lower-powered DMUs, and have pneumatic secondary suspension. Acceleration is improved, at 0.54m/s2. A 4-car unit carries 1092 passengers.
BG DHMU’s have two 350hp underfloor engines (Cummins 855R) driving two separate Voith hydraulic transmissions via propeller shafts and differentials.
Driving cars with power are classified "DPC" (driving power car). Non-engine driving coaches with cabs are classified "DTC". Trailer coaches are classified "TC".
The HPDMUs were used around Bangalore at first, and some suburban services around Chennai (Beach - Kanchipuram). The first HPDMU units underwent trials at Whitefield near Bangalore in 2000. (09/2000) One HPDMU rake was later in trial operation between Madras and Sulurpet, while another could be seen running in trials between Madras and Arakkonam.
(07/2004) A new aerodynamically shaped DEMU model from ICF has been brought into service on the SCR (Bhimavaram - Narsapur - Vijayawada). The leading driving motor cars of these 8-car rakes have a distinctive appearance with a large sloping oval windshield in one piece and can accommodate 54 passengers; the rear motor car accommodates 72. The other six trailer cars of a rake accommodate 84 seated passengers and 240 standing passengers each.
Most HPDMUs have been seen with road numbers in the 14xxx and 15xxx ranges. SCR's DEMU coaches have 150xx numbers for power cars and 154xx for trailer cars.
(03/2021) With gradual increase in electrification around major urban areas, most DEMU operations have been taken over by MEMUs, though some services still remain. Large scale DEMU operations are now seen only in Punjab, where Jallandhar shed homes 90+ units and in the Godavari Delta of Andhra Pradesh, serviced by units from Vijaywada.
In the past, the Secunderbad area also had large DMU operations (including DHMU) on the converted sections between Falaknuma - Medchal - Nizamabad. DMU services on Konkan Railway began in 1997 with a Karwar-Pernem service which was later extended to Ratnagiri. In April 2001, this was curtailed to run on the Karwar-Madgaon section. In the Bombay suburban area, DMUs used to work the Virar - Dahanu Road and Vasai Road - Diva sections extensively.
DEMUs running in the isolated Baramulla - Qazigund section in Kashmir feature two under-slung diesel alternators to enable centralised heating in the coaches. One is used directly in the supply of power, while the other is a standby. These DEMUs also feature a closed off inner compartment with sliding doors and fibre-glass interior panelling.
6 units, each with 2 power cars and four trailer cars, were produced by RCF, Kapurthala between 2003-2005. These units featured a Cummins NT 855 inline 4-cylinder engine developing about 400hp, with a BHEL traction alternator. The first one was commissioned in March 2003 and were trialled in the Delhi - Rewari section. They were then dispatched for use in the Indore-Mhow section of WR. In 2006, two of these were use here. In 2011, MG DEMUs were also spotted in WR’s Mahesana - Taranga Hill section.
With the conversion of almost all MG lines to BG, these DEMUs are presumed to have been scrapped.
Historical note: The RCF rakes were not the first MG diesel multiple units. Fiat supplied some for the Chennai area in 1955. These were diesel-hydraulic units (confirmation needed).
Other diesel units
Several self-propelled Medical Relief Trains (MRT's) are also in use; these use two Cummins 375hp underfloor diesel engines and are thus rather like DMUs although of course they are used for accident relief operations and not passenger services. The transmission is hydraulic. An MRT has one coach with medical facilities and one driving car with the engines. These MRTs are made by RCF. ICF makes 3-car accident relief/medical relief rakes.
Q. In what formations do DMU's run?
HPDMUs have four cars (one DPC and three TC), so the most common configuration for these are 8-car formations. Some busy sections in Punjab also have 12-car formations. 16-car formations were tested, but not adopted.
Lower power DMUs (and DHMUs) are seen in 3-car units, with one DPC, one TC, and one DTC each. 6 car formations are the usual, although 9 cars (with two power cars, one at either end) are also found. In the early 2000s, WR ran 12-car formations on its Ahmedabad - Abu Road section.
In the past, Diva - Roha trains and KR passenger trains often had a diesel loco (WDM-2) at the head and a DMU in the middle of the rake.
Mumbai Area EMU Numbering and Classification
With the advent of MRVC rakes in 2007, CR adopted WR’s numbering and classification conventions. (See CR’s historical scheme below).
EMU rakes in Mumbai are made up of three to four 'units'. Each unit consist of three coaches – A, B and C. The details of the A, B and C coaches are as follows:
- "A" coach: This coach is a normal trailer coach. Half of the coach is a first class section and the remaining half is second class.
- "B" coach: These are the motor coaches. The coaches have traction motors, pantographs and other operating equipment. The entire B coach has general second class accommodation.
- "C" coach: These are the coaches driving cabs/section reserved for the physically challenged. C coaches are present at both the ends of any train. These two coaches have driving cabs. But, there are "C" coaches in the middle of the rake too. These coaches have a section for physically challenged persons instead of the driving cab. Previously, this section was no larger than the driving cab. But in the rakes manufactured in the last few years, the size of this section has increased. WR is also modifying their older coaches to increase the capacity of the handicapped section. The coaches have a general second class section and a luggage section.
In the past, one could tell the zone of the rakes by looking at the numbers, but this is no longer the case. (03/2021) Presently, there are two series - 107 and 207, shared by both CR and WR. The rake numbers follow the below format:
<series> <coach type> <serial number>
To illustrate, a coach numbered 207 B 022 would mean that the coach is the twenty-second coach of type "B" in the 207 series.
In practice, CR and WR have renumbered all coaches to remove redundancy. They took first digit of series (1/2) followed by the actual number in the series, followed by coach type. So the above coach is numbered 2022 B.
CR and WR combine their A,B and C coaches slightly differently.
C B A - C B A - C B A - A B C
C B A - A B C - A B C - A B C
CR’s Historical Numbering
On CR, a 3-coach unit was classified as 76, 70, or 72, where 76 was the leading motor coach (had driving cab if at either end of rake, and reserved seating for handicapped persons when in the middle of the rake), 70 was the motor coach with a pantograph and traction motors (usually had only second-class general accommodation), and 72 was the trailer coach (usually with half first-class accommodation and half second-class). So a nine-coach train had three units in the following sequence: (76-70-72) (72-70-76) (72-70-76).
In the early to mid-2000s, a few odd coaches broke this system and had classifications of 86, 80, and 82. These were thought to be coaches transferred from other zonal railways, particularly WR, which had gotten a jump start on receiving newer AC-DC rakes. The 8xxxx coaches did not appear to have been transferred in 3-coach units, but as singletons.
All Jessop-built CR EMU coaches were allocated a number range between 101 and 399, although the last ones were 350-351-352 homed at Sanpada shed in April 2004. ICF-built ones ranged from 401 through 590 and beyond to a few 6xx numbers. The ones in the 500-590 range were newer (1990s) coaches. Above 524-526, CR stopped maintaining rakes with sequentially numbered units – newer coaches with higher numbers were simply attached to older rakes as required.
In March 2002, coaches numbered 701-715 were introduced, manufactured by BEML with traction systems from BHEL. In early 2004, new rakes with serial numbers in the 8xx range were introduced. These were ex-WR, repainted at the Matunga Workshops.
In 1998, there was also a 900 series rake, which was a complete 9-car set transferred from WR. It was formed with the standard 76-70-72 classification, but the motor coach of the original rake was replaced by one in the 500 series.
Other oddities: Rake 72349 was marked with class 'YTFS'. Rakes 72570 and 72574 were marked 'YSFY' instead of 'YFYS'.
Prefixes and Suffixes: Around 2002-2003, CR EMUs were also seen with a prefix 'O' before the coach number (e.g. O-72146). All coaches in the 86-80-82 combination had a lower-case 's' as a suffix (e.g. 86234s). 'T' was a rare suffix seen on at least one coach: 72185T. Another suffix ‘c’ was also seen. Significance of these prefixes and suffixes is not known.
WR’s Historical Numbering
WR’s numbering and classification continues to this day (see above).
However, 1928 and 1950 EMU stock had a different letter suffix scheme. The configuration of an 8-coach rake then was 'A-B-C-D-D-C-B-A'. With 1928 stock, the 'D' coaches on the Virar side were first class, and part (quarter) of the adjacent 'C' coach with ladies' first class.
With 1950 stock, 'A' and 'D' were both motor coaches. Half of the Churchgate side 'C' coach was the men's first class and the Virar side 'C' coach was half men's first class and half ladies' first class. Later an extra motorcoach was added to each rake. With the 1928 stock, the extra motorcoach was added between two units: 'A-B-C-D-B-D-C-B-A'. For 1950 stock, a custom trailer coach by Jessop was added between the units: 'A-B-C-D-T-D-C-B-A'.
Until the early 2000s, the oldest rakes in use were in the 5xx series. These were originally numbered 1xx and were introduced around 1965. They were withdrawn in 2011. WR rakes are numbered roughly in chronological sequence. Originally simple sequential numbers were used, but when new Jessop rakes were introduced in the 1960s, the existing rakes were renumbered.
- 001 - 040 : 1928 Cammell-Laird / BTH stock. All withdrawn, in use until the 1970s. Not renumbered.
- 041 - 052 : 1950 Metro Cammell rakes, renumbered to 101-112.
- 053 - ?? : 1960-1961 converted Jessop stock, originally made for ER. Renumbered later to 2xx.
- 07x+ : SIG rakes
- ?? : MAN rakes from Calcutta awaiting conversion from 3kV to 1.5kV at Kandivali (KILE) shed. (These became the 4xx series, see below.)
- 101 - 118 : Original numbering of old Jessop rakes, later renumbered to 501-518.
- 101 - 112 : Renumbering of 1950 Metro Cammell rakes. Formerly numbered 41 through 52.
- 201 - 2xx : 1960-1961 Converted Jessop rakes (made originally for ER). Formerly numbered 53 onwards.
- 3xx : 1963 ICF rakes. These numbers were re-used for the AC-DC EMU rakes from ICF/BHEL. Some of these BHEL 3xx rakes were transferred in 2005-06 to CR.
- 400+ : MAN rakes from ER converted to 1.5kV DC from 3kV DC. Original numbers? Probably just after the SIG rakes in sequence.
- 500+ : Jessop rakes. 501 through 518 are the older ones. All were scrapped by February 2011.
- 600 : ICF rakes. All were scrapped by February 2011.
- 701 - 703 : Standee train by ICF. All were scrapped by February 2011.
- 8xx : Jessop rakes. Some of these were transferred to CR 2010, where they retained their WR style numbering. They’ve all been scrapped.
- 9xx : ICF rakes. These rakes were converted to AC-DC traction. All now scrapped (March 2021).
- 10xx : Originally ICF, later renumbered to 9xx. Now 10xx are MRVC rakes.
July 2006 bombings on WR EMU's
Perhaps of some interest to number crunchers, the EMU coaches in which bombs exploded in the terror attacks of July 11, 2006 in Mumbai were: 849-A, 0528-A, 935-A, 634-A, 846-A, 864-A, and 8003-A.
Railcars & Railbuses
Q. Where are railcars or railbuses operated?
Historically, many sections have seen railcar or railbus service in India. There have been several imported models used, and also homegrown versions which are often literally buses or truck bodies placed on rails. In recent times, increased use of railbus or railcar services probably began with the Merta City - Merta Road service in the 1980's. This section still runs BG railbuses.
BG railbus service is also found on the Bangarpet-Kolar, Mathura-Vrindavan, and Bobilli-Salur routes.
The Kanpur-Brahmawart railbus service (early 1990s) was withdrawn in the early 2000’s, with the the Tumsar Road - Tirodi service (introduced in 1998), replaced by a full fledged passenger rake by 2005. Beas - Goindwal Sahib had a long standing railbus service until the mid-2010s when the line was extended beyond to Tarn Taran with DEMUs taking over operations.
MG railbuses were found in several places (Silchar-Jiribam, Junagadh-Dhari, Tiruturaipundi-Agastiampalli, Banmankhi-Bihariganj, Shimoga-Talaguppa, Ambliyasan-Vijapur-Adraj Moti of WR, etc). Many branch lines in NER also had extensive railbus services.
Sometimes two railbus units were operated together, making them technically a railcar formation. The well-known railcar service for Bangalore/Yeshwanthpur operated this way.
Yelahanka- Kolar Gold Fields - Bangarpet had an NG railcar service in the past. When conversion to BG began, these (4 in number, class ZRD) were transferred to the Shimoga-Talaguppa section. There the local workshops rebuilt the under frame for the wider gauge and mated it to a Ashok Leyland engine. A view of one of these appears in Bill Aitken's Exploring Indian Railways.
Bankura-Damodar, Bankura-Rainagar, Bodeli - Chota Udepur were other NG sections with railbus service. In July 2000, Ankleshwar - Raj Pipla was also supposed to get NG railcar service. In these NG railcars, the power car were to have a 22-passenger capacity and the trailer cars a 31-passenger capacity. However, these never materialised and line was later converted to BG.
There was also an NG railbus service between Kalka and Shimla but now single-unit railcars work the line as special, chartered services. Shantipur-Nabadwipdham was another section with railcars. Barddhaman-Katwa and Ahmadpur-Katwa also had railbus service.
Some railbuses and railcars were made by the Izzatnagar works by placing road vehicle bodies on wheels modified for the rails. The older railbuses often have an Ashok Leyland bus engine with a Hindustan Motors hydraulic transmission (under licence from Allison).
RDSO developed a BG railbus design with 60 seats, powered by a normal bus engine and suitable for bidirectional running, in 1993. BEML manufactures these with some modifications in the power pack.
The Length: 10.7m; width: 3.2m; height: 3.65m; wheel-base: 7m. Tare weight is 16t and gross weight is 24t. The body is all steel, with an integral shell design of formed and rolled sections welded together.
Max. speed 60km/h. Engine: inline 6-cylinder, with mechanical variable speed governor, 175hp. Transmission: automatic hydraulic with twin turbine torque converters. (Allison torque converter, made by Hindustan Motors.) Drive: single driven axle (axle-mounted bevel gear drive with single stage reduction). Brakes: Service brakes use compressed air; there are also standby brakes (with separate brake valves) in case of main brake failure, and air-assisted parking brakes.
There are driving cabs at each end of the railbus, each with access through sliding doors one on the side and one leading to the passenger compartment. A door in the middle of the railbus leads to the passenger compartment.
Axle/wheel capacity is 13 tonnes; wheel diameter 915mm. Suspension: single-stage with vertical guide, helical spring, and shock absorber. Electricals: 24V 180Ah lead-acid battery for starting, controls, lighting; 24V 45A alternator.
Other Self-propelled Vehicles
There are some OHE inspection/maintenance vehicles that use the same prime mover (Cummins 705hp engine) as the DEMU's; these are called diesel electric tower cars (DETC) as they have a diesel-electric transmission. (The term 'tower wagon' is also used instead of 'tower car'.) These can often be seen used for light shunting duties since the 700/750hp engine is powerful enough for that. Most DETC vehicles are built by ICF. A DETC generally has a top speed of about 100km/h. It is equipped with dual brakes. It has a compact workshop for routine maintenance and repairs of the OHE structure, and a telecommunications unit for communicating with the traction power controllers. Most DETC units also have small rest and toilet areas for the crew.
Some OHE maintenance vehicles have a different, smaller engine from Ashok Leyland with hydraulic transmission. The newer ones (class RU) have 8-wheeled bogie stock in contrast to the older 4-wheeler OHE inspection cars (class ERU). They have an all-weather cockpit at roof level for OHE inspection, and a hydraulically operated tower which can be swung up close to the catenary (also sideways to the catenary of the adjacent track). Pantographs with measuring devices allow recording contact wire pressure and stagger, as well as dynamic characteristics of the catenary on the run.
They also house a workshop inside, with machine tools, welding equipment, portable generator, etc., in addition to sleeping/resting quarters for the crew, including toilets and a kitchenette, a rare level of crew comfort on IR.
The BEML OHE inspection cars can run at 110km/h (the older ones could only manage 40km/h and besides, were often in trouble because they had a flaw where they failed to trip the block circuit in many cases). The new ones can also work as wiring trains in case the catenary needs to be rewired (for short lengths of catenary). These cars have driving cabs at both ends.
The older ones (class ERU) exhibit a wide variety in their designs. Most were 4-wheeled, although a few 8-wheeled ones exist(ed). Many were put together by the various loco sheds and workshops. Some old ones even had mechanical transmissions with a manual gearbox in the cabs at either end, often rigged from road truck powertrain components. A few less powerful OHE inspection cars are also seen; these have a small air-cooled engine and a minimal walkway on the roof for getting close to the catenary.
There are two versions, one with a powerpack consisting of a single 6-cylinder diesel engine of 530hp capacity (KTA 19-R, Kirloskar Cummins), and a double unit using two 285hp engines (NT 855-R4, Kirloskar Cummins). Both have roof-mounted radiators.
Transmission: Automatic, continuously variable hydraulic Voith transmission (T 311-r for single unit powerpack (365kW input), T 211-r for the double (194kW input)); terminating in an axle-mounted helical gear drive. Brakes: Compressed air system with integrated brake block units. Service brakes, emergency brakes (with separate back-up emergency brake valve), and mechanical parking brakes are provided. Gross weight 60t; trailing load up to 60t. Length: 22.3m.
Wheels/suspension: Two double-axle bogies with two-stage suspension and box section fabricated frame; 16t solid forged axles. With the single unit powerpack there is 1 powered axle and 3 trailer axles; with the double unit there are 2 powered axles and 2 trailer axles. Wheels have 915mm diameter.
Electricals: 24V system. 320Ah lead-acid battery for lighting; 330Ah lead-acid batter for engine starting; 30V 4.5kW axle-driven alternator for internal lights; 50A 24V engine-driven generator for headlights and other external lighting, control circuitry, etc. Headlights 250W. In addition, a 8kVA diesel generator is provided to supply power to the inspection tower platform and for the workshop's tools.
Accident Relief Medical Vans (classification ARMV) are diesel-powered. In some cases they are actually converted EMU units (e.g., old DC EMU's from the Bombay area are used as ARMV's on KR), with a diesel-generator set added. Usually two such EMU units are coupled together, one supplying the power and the other converted to house an emergency medical treatment facility, where the diesel-generator supplies power for air-conditiioning, etc. The hospital units have emergency medical equipment and surgical facilities. Usually, they also have accommodation (hospital beds) for up to 12 patients on board. ICF usually refers to these coupled units as ARTV (below). Max. speed 95km/h.
Accident Relief Tool Vans (classification ARTV) are usually coupled in pairs, one as a hospital coach (see above, ARMV), and another coach with re-railing and metal working equipment and other tools. (The combination is therefore usually denoted 'ARMV/ART'.) They usually have two underslung diesel engines of about 350hp (total 700hp) with a hydraulic transmission (Kirloskar Pneumatics, under licence from Voith). In October 2013, some ARTVs belonging to Chennai Central were seen to operate with three cars, the third one being similar to an OHE wiring car, but its purpose is not clear. Max. speed 95km/h.
SPART In 2004, RDSO developed a design for a three-coach self-propelled ARMV/ART (SPART) train that can be driven from either end and which has a top speed of 140km/h. Classification code not known -- this is identified in RDSO literature as the 'high speed SPART'. In addition to the air-conditioned medical van ('PC') and the tool van ('DPC-II') as with the current two-coach ARMV/ART trains, this one would have an additional supervisory/kitchen van ('DPC-I'). Additionally, compared to the older ARTV, there are some improvements such as a wider sliding door with a ladder arrangement for easy unloading and loading of tools and materials.
Note that accident relief vehicles of different kinds are sometimes generically referred to as Accident Relief Van or ARVs.
NETRA (which stands for Network of Electrification -- Testing and Recording Apparatus) is a special coach designed for inspection of the catenary in electrified sections. It has an IRY shell mounted on IR-20 bogies, with a rated top speed of 160km/h. (It is an unpowered vehicle and must be hauled by a loco.) It has a pantograph (a dummy -- does not draw current) which is used to test and record various mechanical characteristics of the pantograph-catenary interaction while the coach is in motion.
ARTs and Breakdown Cranes Breakdown cranes have always been essential equipment for emergency operations at accident sites. Steam cranes were part of IR's inventory for a long time, even after steam-hauled trains had essentially disappeared from the network. However, steam cranes have been decommissioned now and diesel cranes are used instead. Breakdown cranes form a part of Accident Relief Trains (ART) which are like the ARTV rakes discussed above but carrying additional heavier tools, hydraulic rerailing equipment, and with a breakdown crane usually forming part of the rake. Often they also include a medical van, thus combining the features of both the ARTV and the ARMV.
In the past, there were many different formations of ARTs and their composition was not entirely standardized. Two classes, known simply as 'A' type and 'B' type ARTs, were usually recognized. The 'A' type ARTs were the ones equipped with heavier-duty equipment, although there was no firm line dividing the two. In the late 1970s, there were 141 'A' class ARTs and 60 'B' class ARTs on IR's network.
The introduction of heavier rolling stock (such as the BOX and other wagons that were replacing the earlier 4-wheeler stock) made it imperative that breakdown equipment be capable of dealing with heavier loads during operations of clearing accident sites, rerailing vehicles, etc. The older steam cranes were often not up to the task. Accordingly, in 1981 the Railway Board decided that all new breakdown cranes had to be diesel-powered and rated for 140t on BG and 75t on MG. Hydraulic rerailing equipment and medical vans were made standard for ARTs as well. The classification of ARTs was then rationalized so that 'A' class ARTs always included a heavy-duty breakdown crane, and were to distributed so that no accident site would be more than 250km from one. The 'B' class ARTs would no longer have a breakdown crane but would be distribed more closely so that no accident site was more than 150km away from one. With this, the required number of ARTs under the new scheme was intended to be 151.
The 1981 requirements for breakdown cranes included the following: 140t rated lifting capacity, max. speed of 75km/h, provision of safe load moment indicator and safety cut-offs, and all-hydraulic motion actuation and control. Twelve cranes were obtained from NEI Cowans Boyd and twelve from Gottwald. In each case, 6 cranes were imported assembled, 3 in knocked-down condition, and 3 in component form. Jessops in Calcutta were entrusted with the production of Cowans design cranes, and Jamalpur workshops with the production of Gottwald cranes. Jamalpur workshops began indigenous production of Gottwald cranes by 1986.
Smaller breakdown cranes (80t, 120t, etc.) are also used by IR. In IR documents, 'small' cranes are those that have load moments up to 700 tonne-meters; 'medium' cranes those which have load moments from 700 to 1,000 tonne-meters, and 'large' cranes those which have load moments above 1,000 tonne-meters. The 140t cranes (Cowans / Gottwald) can lift the 140t load at a radius of 9m, so that their load moments are 1,260 tonne-meters and are therefore considered 'large' cranes.
There are many other self-propelled vehicles such as inspection trolleys (well, the simplest of these are human-powered!), track-laying equipment, oscillograph cars, with various kinds of low-power diesel engines. Road vehicles such as trucks, buses, vans, and even small scooters (Vespa, Lambretta, etc.) are sometimes seen modified for use on the tracks.