WAM-4 Acceleration

Here are some timings of a WAM-4 clocked from the cab at various stations on the line. The difference between mainline platform stations and loop line stations restricted to 30km/h is clearly seen in the figures below. The train was the Maharashtra Express going towards Nagpur with 16 coaches. This is provided as indicative information only and does not necessarily represent typical or usual driving practices or loco performance on this or other sections.

Station: Sewagram (SEGM) (mainline platform)
Speed (km/h) Time taken
20 01:01
40 01:49
60 02:28
80 03:02
100 03:40
105 04:03

Conditions: Assisted in part by a roughly 3km long down-gradient starting from outside the station limits. However, notching not aggressive. Max amps were only about 850.

Station: Seloo Rd. (30 km/h loop line platform)
Speed (km/h) Time taken
20 00:53
40 03:04
60 03:41
80 04:43
100 06:13
105 06:39

Conditions: Aggressive notching at the beginning till 25km/h. Loco was running at 11th notch in the loop line! Notice how much the loop line influences overall timings. Max speed figures skewed in major part due to neutral section a few km later. Also slight upgradient for majority of the acceleration curve.

Station: Tuljapur (TJP) (30 km/h Loop Line platform)
Speed (km/h) Time taken
20 00:56
40 02:25
60 03:31
80 04:21
100 05:50
105 Not reached

Conditions: Slightly less aggressive this time. Ninth notch was used to pick up speed on the loop line. Again, upgradient and loop line marred performance.

Station: Sindi (30 km/h Loop Line platform)
Speed (km/h) Time taken
20 01:04
40 02:32
60 03:10
80 04:03
100 05:01
105 05:25

Conditions: Almost level ground with reasonable notching. Even aggressive notching in all these cases left something to be desired. We almost never reached the 900 amp mark during acceleration. Apparently the driver was leaving himself a wide margin.

Station: Borkhedi (mainline*)
Speed (km/h) Time taken
20 00:55
40 01:38
60 02:28
80 03:20
100 04:00
105 04:12

(*) Starting up from mainline after unscheduled halt to drop off someone.

Conditions: Very aggressive notching up this time. Current to TM4 went up to 1000 amps for the first time during acceleration. Terrain pretty much flat until acceleration.

In all the above cases brakes were completely released before starting up.

Below is a summary of the times taken to achieve various speeds.

20 01:01 00:53 00:56 01:04 00:55
40 01:49 03:04 02:25 02:32 01:38
60 02:28 03:41 03:31 03:10 02:28
80 03:02 04:43 04:21 04:03 03:20
100 03:40 06:13 05:50 05:01 04:00
105 04:03 06:39 Not reached 05:25 04:12

As can be seen, it can take an additional two minutes or more to re-attain a speed of 100km/h each time a loop line of 30km/h is encountered, in comparison with mainline runs through station limits; this doesn't include the delay caused by slowing down on approach to the station. Many loop lines are speed-limited even further, to 15km/h. A 16-coach train is the perhaps the best one for seeing the WAM-4 loco perform at its best, unhindered by excessive loads. The bottlenecks seen here were the speed-restricted loop lines more than anything else on the route.

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