Changing loco cabs

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These are the precautions to be taken while changing cabs in electric locomotives.

It is important from a safety standpoint to follow the proper procedures while changing the cab of the locomotive. Problems of brake failure, insufficient pressure, etc., are sometimes overlookd when switching cabs.

A. CAB CHANGING IN SINGLE LOCOMOTIVE

Perform the following actions:

  1. Application of locomotive brake with SA 9
  2. Switch off the DJ and lower the pantograph.
  3. Remove the ZPT key, BL key and the MPJ from the cab.
  4. Close the isolating cock of the locomotive and train brakes in the cab and put the handles of the locomotive brake and train brake in release position.
  5. Go to the other cab and put the BL key, ZPT key and MPJ key in position. The ZPT key should be in the appropriate position to raise the pantograph.
  6. The DJ should be closed and the MPJ handle should be moved to forward position.
  7. The isolating cock of SA 9 and A 9, i.e., the locomotive brake and train brake, should be opened and the brakes should be released by moving the handle of locomotive brake in released position.

B. CAB CHANGING IN MULTIPLE LOCOMOTIVES

The steps above for the single locomotive case must be followed first.

The following *additional* points are to be followed in the case of multiple locomotives when switching cabs from one locomotive to another.

The position of the MU2B valve in the locomotive, which will work as trailing locomotive, should be kept in 'trail' position. Similarly the lead and trail cock should be opened in leading locomotive and closed in trailing locomotive.

The position of the MU2B valve in leading locomotive should be kept in the 'lead' position.

In the trailing locomotive, the locomotive brake handle and the train brake handle both should be kept in the isolated condition. The locomotive brake and train brake of the rear cab of the leading locomotive should also be in the isolated condition. The locomotive brake and train brake isolating cocks should be open in the working cab (leading cab) of the leading locomotive.

The position of various cocks in leading and trailing locomotive is given below.

VALVE NAME LEADING LOCO TRAILING LOCO
MU2B Lead position Trail or dead position
A 9 brake valve handle Release.
The handle should be removed from the non-working cab.
Release
The handle should be removed from the non-working cab.
SA 9 brake valve handle Release.
Handle should be available in the driving cab only.
Release
Handle should be available in the driving cab only.
A 9 brake valve cut-out cock Open in driving cab; Closed in rear cab. Closed in both cabs
SA 9 brake valve cut-out cock Open in driving cab; Closed in rear cab. Closed in both cabs
A 9 differential valve cut-out Open Open
H 5 relay cut-out cock Open Open
HB 5 relay cut-out cock : Air-braked train Closed Closed
HB 5 relay cut-out cock : Vacuum-braked train Open Open
Distributor valve isolating cock
(Note: Valve remains open in 6 o'clock position and closed in 9 o'clock position.)
Open Open
Lead and trail cock
(Note: This cock is in cab no. 1 in WAG-5 locos and in cab no. 2 in WAP-1 locos.)
Open Closed
2" size cut out cock (MTP cock)
(This mail train pipe cut out cock is provided near PV1 in corridor No. 1.)
Open Open
Feed pipe isolating cock Closed
(Open only for single-pipe working.)
Closed
(Open only for single-pipe working.)
Auto-drain valve isolating cocks on MR1 & MR2 Open Open
MR equalising pipe angle cut-out cock (white) Open after coupling Open after coupling
Brake cylinder equalizing pipe angle cut-out cock (green) Open after coupling Open after coupling
Brake pipe angle cut-out cock (green) Open after coupling Open after coupling
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