Mumbai Area Electrification
by Vivek Manvi, January 2005
The Mumbai region is the last bastion of 1500V DC electrified lines on Indian Railways. Soon, this region too will be converted to 25KV AC traction, which is the standard throughout the country. The conversion work is in progress in some sections and in fact, AC loco hauled trains now reach the outskirts of Mumbai. Here is some information on the current status and progress of electrification and conversion in and around Mumbai.
Western Railway (WR)
WR lines are electrified to 1500V DC traction from Churchgate to Virar. There are four lines from Churchgate to Borivali and two lines from Borivali to Virar. There is a fifth additional "Suburban Traffic Avoiding" (STA) line between Borivali -Santacruz and Mahim - Mumbai Central. In addition to this, there are two lines for running suburban/harbour line trains between Mahim Jn and Andheri. There is an AC-DC neutral section at Virar and beyond that the lines are energized to 25KV AC. The WR DC EMUs can therefore run only between Churchgate and Virar. The Mail/Express trains on WR are hauled by the dual-voltage (AC-DC) WCAM-1 and WCAM-2 locos. The freight trains are hauled by WCAM-1/2 or sometimes even by CR's WCAG-1 dual voltage freight locos. All these locos change traction at the neutral section on the move. As the loco approaches the neutral section from Mumbai, the DC pantograph is lowered. The loco then coasts through the neutral section and raises its AC pantograph.
Plans have been in place to convert the entire Virar-Churchgate section to 25KV AC since a long time. It is a really huge operational challenge to carry out the conversion work without affecting the suburban EMU traffic, which carries millions of commuters everyday. The first step taken by WR was to convert a couple of its 1500V DC EMUs to dual-voltage AC-DC EMUs capable of running under AC as well as DC wires. These AC-DC EMUs feature the latest equipment such as AC three-phase traction motors, fault diagnostic systems and regenerative braking. Later, ICF-built AC-DC EMUs were also introduced on WR. These featured pneumatic suspension systems in addition to the sophisticated electrical systems mentioned above. All the EMUs on WR will have to be converted to AC-DC before the traction is changed to ensure smooth running of traffic.
On Sundays, WR operates a "Mega Block" in which it carries out major maintenance and upgradation work. These maintenance blocks are now being used to gradually upgrade the OHE and other traction equipment to handle 25KV AC current. This includes replacing the older DC-type insulators with newer ones and insulating the OHE from structures nearby.
Work is also on for quadrupling of the Borivali-Virar section. These lines will be energized to 25KV AC right from the beginning. Additional alignments are being built and are in various stages of completion. Two additional platforms have also been built at various stations in the section. The biggest challenge - the twin Vasai Creek bridges between Bhayander and Naigaon are also almost ready.
The two additional lines between Virar and Vasai Road were completed and thrown open to traffic sometime in May-June 2004. This has proved to be a boon as freight trains hauled by AC locos can now come directly to Vasai Road without a loco change and carry on till Panvel/JNPT port. (The CR section from Vasai Road - Diva - Panvel - Jasai was also converted to 25KV AC sometime in early 2004. For more details, please refer to the Central Railway section below) The change from an AC to an AC-DC loco and vice versa, which used to happen at Dahanu Road/Saphale has now been eliminated resulting in an enormous saving of time. It is now common to see WAG-5 and WAG-7 locos from sheds across the country in this section.
Central Railway (CR)
CR is a more complex system than WR as it has branch lines in addition to the mainline. CR tracks are electrified to 1500V DC from Mumbai CST right upto Pune and Igatpuri. The lines to Pune via Karjat and to Igatpuri via Kasara separate at Kalyan Jn. In addition to this, there is the Harbour line for suburban traffic, which runs from Mumbai CST to Panvel on one end and to Mahim Jn on the other. These two lines separate at Vadala. Then there is the recently inaugurated Thane-Vashi suburban section. All these lines are currently under DC wires. There is also the Vasai Road - Dativli - Panvel - Jasai line, which was converted to 25KV AC in early 2004 to facilitate the running of freight trains hauled by AC locos. This section sees a huge amount of freight traffic, especially high-speed container trains called ConRaj - Container Rajdhanis. These container trains run between the JNPT/Nhava Sheva ports in Navi Mumbai and the Inland Container Depot at Tughlakabad. To enable dual voltage locos to switch over from the Vasai-Diva-Panvel AC lines to the CR DC mainline, there are three AC-DC neutral sections between Diva and Dombivli. The first is at the Dombivli side of the Vasai-Diva triangle, the second in between the Vasai and Panvel triangle, and the third at the Diva end of the Panvel triangle.
CR's DC EMU trains run from Mumbai CST to Kasara on the Igatpuri line, to Karjat (and Khopoli) on the Pune line, to Panvel and Andheri(WR) on the Harbour line and between Thane and Vashi on the newly launched Thane-Vashi section. DC EMUs also run between Pune and Lonavala. The Mail/Express trains on CR are mainly hauled by the powerful dual-voltage (AC-DC) WCAM-3 locos. Pure DC locos such as the WCM-x class have become extinct and the only DC locos which exist today are the WCG-2 freight locos. These too are rarely used on freights and mainly serve as banker locos in the ghat sections on CR i.e. Karjat-Lonavala on the Pune line and Kasara-Igatpuri on the Igatpuri line. It is common to see consists of two and sometimes three WCG-2 banker locos in these sections. The DC EMUs are not allowed to run in the ghat sections due to the steep gradient in the range of 1 in 40.
The lines beyond Igatpuri on CR are energized to 25KV AC. Mail/Express trains coming from Mumbai and headed by dual-voltage WCAM-3 locos running under DC mode arrive at Igatpuri and switch over to an AC loco here. Although the WCAM-3s can run under AC wires, they rarely venture away from the region due to their limited numbers. Here, the traction changeover system is a bit different. In place of an AC-DC neutral section, the current in the OHE at the station changes from DC to AC and vice versa.
The lines beyond Pune are not electrified. Mail/Express trains coming from Mumbai and headed by dual-voltage WCAM-3 locos running under DC mode arrive at Pune and switch over to a diesel loco here. There is a new line under construction between Panvel and Karjat. This will apparently reduce the traveling time between Mumbai and Pune by atleast 30 minutes. This line will be energized to 25KV AC right from the beginning.
Panvel station on CR is unique as it has both AC and DC traction. There are two separate platforms under DC wires for the CSTM-Panvel EMUs and three platforms under AC wires for the trains on the Diva-Panvel-Jasai line. Beyond Panvel is a non-electrified single line section upto Roha. Beyond Roha is the Konkan Railway line going towards Ratnagiri, Madgaon, etc. However, mail/express trains to/from Konkan Railway are diesel hauled right from Mumbai as Panvel currently does not have facilities for loco and crew change.
Similar to WR, the biggest challenge on CR is to convert its lines to 25KV AC without affecting the suburban traffic. Currently, CR does not have any dual-voltage AC-DC EMUs. All the DC EMUs will have to be converted to AC-DC before the traction is changed, so that the millions of daily commuters do not get affected. Another challenge is to carry out the conversion work in the two ghat sections of CR, which have steep grades as high as 1 in 40. CR also regularly carries out maintenance blocks on Sunday to maintain and upgrade its existing systems. It too has been using these blocks to convert the OHE equipment in some places to handle 25KV AC.
All in all, it will take atleast two years for the conversion to be complete on WR right up to Churchgate. On CR, it will take atleast four-five years for the entire section to be converted to 25KV AC. We can hope that by the end of this decade, we will be able to see AC locos hauling mail/express trains out of both Mumbai CST and Mumbai Central. Things are already happening with the arrival of the WAGx locos. Exciting times for a rail fan to be in Mumbai!!!
Mumbai Area Electrification - Addendum
(Updated - 21st February 2006)
The Challenge
After more than three years of sustained efforts, CR finally converted the Kasara-Igatpuri section to 25KV AC traction on February 19, 2006. This conversion too had its own share of problems - the imposing Thull ghats, the non-availability of AC-DC EMUs, non-availability of AC locos for banking! Add to this the recent floods in Mumbai and the subsequent washing away of tracks and OHE equipment over large stretches of track. However, the CR authorities were resolute as if they had a point to prove to someone!
The Effort
The Thull ghats were conquered first - AC substations were built at various locations including one at Kasara. An AC-DC neutral section was built about 2.5km south of Kasara. Next, AC-DC EMUs were transferred from WR to CR. In all around 9 ICF built AC-DC EMUs were transferred to CR. This included one with the three MRVC coaches. In return, WR got old DC EMUs from CR. Finally, WAG-5 locos from Bhusaval were brought to Kasara to serve as bankers. On the D-day, a total power block of around 5 hours was imposed in the Kasara-Igatpuri section. Confirmation trials were carried out and the section was energized to 25KV AC. The first train to run under AC wires although only for 2.5 km was an AC-DC EMU bound for Mumbai CST, which was flagged off by a senior gangman in the presence of the GM, Central Railway. The first train to ascend the Thull ghats under AC wires was a freight train which was surprisingly hauled by twin MU'd WCAM-3 locos banked by triple WAG-5 bankers; the first mail/express train to ascend under AC wires was the Godaan Express. With this, history was created as the first of the only two ghat sections under DC wires joined numerous others on IR as it was converted to 25KV AC. This also ended the era of the WCG-2 DC locos in the Kalyan-Kasara-Igatpuri section. These howling beasts would surely be missed by one and all. The mainline hauling duty in this section will be still done by the standard workhorse of CR - the WCAM-3 although under AC mode. This is because of the lack of electric loco stabling/maintenance facilities at Kasara and the existence of these just a few km away at Igatpuri.
Next steps
With the Kasara-Igatpuri section converted to AC, the next logical step for CR would be to convert the Kasara-Kalyan section. The Kasara-Kalyan section can be easily converted in a handful of months if CR gets a few more AC-DC EMUs to cater to the Asangaon and Titwala services. The new AC-DC neutral section would be just south of Shahad station. From then on, the challenge would be enormous as taking AC into Kalyan would mean dozens of more AC-DC EMUs, complex switchovers, neutral sections on points and re-modelling of yards. Before this can happen, CR would think about converting the Pune-Lonavla-Kalyan stretch to AC so that there is no need to maintain separate AC & DC platforms at Kalyan. Looking at the pace at which CR is going about its work, one can estimate that it would take atleast a whole year if not a year and a half for AC traction to enter Kalyan.
The Counterpart!
On WR, things have been moving at quite a leisurely pace. After the initial euphoria of the commissioning of the additional pair of lines between Virar and Vasai Road, there has been hardly any movement. The re-settlement of slum-dwellers at Dahisar for the Borivali-Virar quadrupling project had been taking ages and was finished only around the end of 2005. WR's AC ambitions received a further setback when its newer ICF built AC-DC EMUs were transferred to CR to help them convert the Kasara-Igatpuri section. However, the laying of additional tracks between Vasai Road and Borivali is in an advanced stage now and will soon be completed. Even if this gets completed, WR will not be in a position to augment its services till it gets atleast a dozen more AC-DC EMUs. Once these arrive, it will make life easier for the already harrowed commuters traveling to the far flung suburbs such as Bhayandar, Vasai & Virar. The two new tracks will be under AC traction throughout and simultaneously the existing tracks will be converted. The new AC-DC neutral section would shift to a point just north of Borivali station. This can be estimated to be completed by the end of 2006. As is the case with CR, the entry of AC traction into Borivali and beyond will be challenging with dozens of AC-DC EMUs needed.
In the past year or so, we have seen small but positive steps being taken to convert the last bastion of DC into AC. Although, there have been some great milestones achieved, it will be atleast three to four years more till the entire section till CSTM/Churchgate gets converted to AC. So - fans of WAP-4s and WAP-5s - you will have to wait atleast till the end of the decade to see your favorite beasts screaming through Mumbai.