The Neutral Zone

by: VIRAF MULLA

A certain event on the Indian Railways is soon to pass into history. The event occurs day in and day out, every few minutes, and with every train, and takes place at Virar, some 60 km from Bombay, on the Western Railway.

This is the switching of pantographs from d.c. to a.c., and vice versa, and it happens while of the run. The Western Railway lines out of Churchgate and Bombay (Mumbai) Central are electrified on 1500 V d.c. upto Virar, after which it is 25,000 V a.c. To avoid the necessicity of a locomotive change just 60 km out of Bombay, and to avoid a long halt at that Virar merely to change engines, the Western Railway uses dual current electric locomotives of class WCAM/1 and WCAM/2. Of the locomotives' two pantographs, one is for a.c., and the other for d.c. These can be interchanged in the event of an emergency, but it does not generally occur.

These locomotives begin their journey from Bombay Central on 1500 V d.c. All this time, the d.c. pantograph is up. Just after Virar, the train enters a dead zone, i.e., there is an overhead wire, but it is not charged. While coasting through this dead zone, the locomotive lowers its d.c. pantograph, then raises its a.c. pantograph, switches on the power again, and continues on its way. No stops, no fuss, no delays, and no coughs or splutters. Exactly the reverse occurs on the return journey: the a.c. panto is lowered as the train enters the neutral section, the train coasts while the engine raises its d.c. pantograph.

Many Bombayites are not even aware of such a wonder occuring in their own backyard. And those who do, probably don't care. But with the conversion underway of the d.c. lines to a.c., this event will soon become history. No more neutral zone or pantograph raising and lowering. By 2002, straight a.c. engines will run right into, and out of, Bombay (Mumbai) Central. It is important to document this event before only memories remain. After all, we shouldn't regret having overlooked what is soon destined to be a part of IR history.

Five irfca members (Shrinivas Joshi, Viraf Mulla, Apurva Bahadur,  Rajan Mathew and Venky) undertook a trek past Virar into the netural zone in May 2001, and attempted to capture on film the motions of this d.c. to a.c. (and vice versa) switchover.

Here are my pictures from that trip:

For the technical minded, CLICK HERE FOR SOME ADDITIONAL INFORMATION about this entire operation, kind courtesy of Prakash Tendulkar.

 

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Instructions for the driver to lower d.c. panto.

1.  Instructions for the driver to lower d.c. panto. (CLICK ON THE LINK IN THE PURPLE BOX ABOVE FOR SOME ADDITIONAL INFORMATION ABOUT THIS OPERATION).
2. 9022 Surat - Mumbai Flying Ranee about to enter the 'Dead Zone' from a.c. section with panto still in position.

9022 Surat-Mumbai Flying Ranee about to enter the 'Dead Zone' from a.c. section with panto still in position.

147 Virar-Surat Shuttle lowering the panto in the 'Dead Zone' from the d.c. end.

3. 147 Virar - Surat Shuttle lowering the panto in the 'Dead Zone' from d.c. end.
4. WCAM/1 # 21815 enters the 'Dead Zone' from the a.c. end with both pantos fully lowered.

WCM/1 # 21815 enters the 'Dead Zone' from the a.c. end with both pantos fully
    lowered.

Another WCAM/1 hauling a container train from the a.c. end. Both this pic and the previous one were clicked by me parched halfway up the catenary mast.

5. Another WCAM/1 hauling a container train from the a.c. end. Both this pic and the previous one were clicked by me perched half way up the catenary mast.
6. The 2952 Rajdhani in the d.c section about to cross the 'Narangi' Bridge.

The 2952 Rajdhani in the d.c. section about the cross the 'Narangi' bridge.

Taken in a sequence, this event would appear as under: Note that this is merely a simulation, to show the order of events: the pictures are not shot in this sequence. But if one did so, the event would appear thus:

Train enters Neutral 'Dead' Zone with d.c. pantograph up. a. Train enters Neutral 'Dead' Zone with a.c. pantograph up.
b. The a.c pantograph is lowered, current switched off. The d.c. pantograph is lowered, current switched off.
The train coasts through the neutral section with both pantos down. c. The train coasts through the neutral section with both pantos down.
d. The d.c. pantograph is raised and current switched on. The a.c. pantograph is raised and current switched on.
The train continues on its journey in a.c. territory with the a.c. panto now fully up. Sorry about the changed loco! e. The train continues on its journey in d.c. territory with the d.c. panto now fully up. Sorry about the changed locomotive!

This sequence will be reversed when the train comes into a.c. territory from d.c.

WDM/2 # 18898 hauling the Secunderabad-Rajkot Holiday Special in the 'Dead Zone'.

7. WDM/2 # 18898 hauling the Secunderabad - Rajkot Holiday Special in the 'Dead Zone'.
8. 14 Valsad - Mumbai Central Fast Passenger on May 1, 2001.

14 Valsad-Mumbai Central Fast Passenger on May 1, 2001.

Although the process of conversion of the d.c. lines around Bombay (Mumbai) is slated for completion by 2005, the Bombay Central - Virar lines will be completed first, probably even by 2002. This if course means a painful transition period, for the suburban lines carrying five million passengers daily at trains running at three minute intervals is not a joke. Any disruption in rail services will cause the teeming megapolis to grind to a screeching halt, and it will be chaos of unmanageable proportions.

Proposals put forth to tide over this crisis include a high horsepower high capacity diesel-electric multiple unit (HPDEMU) and a dual current a.c./d.c. electrical multiple unit. While the HPDEMU is undergoing trials in Southern India, an a.c./d.c. e.m.u. was recently spotted at the Kandivli e.m.u. shed in Bombay. Here are a few pictures of that unit, shot by me from a Churchgate-bound local.

A far shot of the a.c./d.c. e.m.u. in the Kandivli shed in Bombay. These pics were clicked by me from a Churchgate bound local train.

9. A far shot of the a.c./d.c. e.m.u. in the Kandivli Shed in Bombay. These pics were clicked by me from a Churchgate bound local train.
10. An attempt to enlarge only the local in the scan.

An attempt to enlarge only the local in the scan.

Side view of the a.c./d.c. e.m.u. unit.

11. Side view of the a.c./d.c. e.m.u. unit.
12. A general view of the a.c./d.c. e.m.u. in Kandivli shed. Note the cream livery of the first class car.

A general view of the a.c./d.c. e.m.u. in Kandivli shed. Note the cream livery of the first class car.

A view of the motor coach of the a.c./d.c. e.m.u. Note single arm pantograph with twin collector shoes for d.c. territory.

13. A view of the motor coach of the a.c./d.c. e.m.u.  Note single arm pantograph with twin collector shoes.

Thats is then. You might also like to check out Apurva Bahadur's Dead Zone page for comparison.

Comments? Questions?

Please e-mail me at:    sncf@godrej.com

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