LOCO-4412 Locomotive — Traction Motor and HEP Isolation
Traction motor change on a road locomotive in the shop. Covers main generator excitation, head-end power at 480V, the battery bank that cannot be switched off, and movement restraint on a vehicle that is itself the hazard.
How Setyr addresses Rail →
It refers to equipment that does not exist and illustrates the elements 29 CFR 1910.147(c)(4)(ii) requires a procedure to contain. It is not a document to adopt. Under (c)(4)(i) the employer must develop and document energy control procedures specific to their own machines, and under (c)(6) must inspect them at least annually.
12 points, in sequence
Wheel chocks and derail on the shop track.
Method: Chock both sides of one axle and set the derail at the shop track entrance. Must be ENGAGED.
Caution: The derail protects the crew under the locomotive from a movement elsewhere on the track. It is not optional because the shop is quiet.
Locomotive hand brake, applied on the truck being worked.
Method: Apply the hand brake fully and confirm the chain is tight. Must remain APPLIED.
Caution: Bleeding main reservoir air releases the air brakes. The hand brake becomes the only restraint on a vehicle on shop track.
Prime mover engine start control and fuel rack, isolated at the engine control switch.
Method: Place the engine control switch to ISOLATE and lock. Confirm the engine cannot be cranked from either control stand.
Caution: A locomotive has two control stands. Isolating at one does not disable the other.
Main generator field excitation breaker.
Method: Open and lock the field breaker. Prove no excitation at the generator terminals.
Caution: A rotating generator with residual field produces voltage at the traction motor even with the throttle at idle.
Traction motor cutout switch for the motor being changed.
Method: Open the cutout, lock, and prove dead at the motor leads in the traction motor junction box.
Caution: Cutting out a motor at the switch does not de-energise the common DC bus it shares with the others.
Traction converter DC link capacitor bank.
Method: Allow the DC link to discharge for the full time, then confirm below the safe threshold with an approved meter before opening the converter cabinet.
Caution: The DC link holds a lethal charge long after the engine is shut down. Time alone is not the verification; the meter reading is.
Head-end power contactor and 480V trainline supply to the coaches.
Method: Open the HEP contactor, lock, and prove dead at the trainline receptacle.
Caution: HEP can be supplied from the adjacent locomotive through the trainline. Isolating this unit does not de-energise the trainline.
Shore power connection at the shop stand.
Method: Disconnect shore power and lock the shop stand receptacle.
Caution: Shore power backfeeds the auxiliary bus and keeps cab systems live with the engine shut down.
64V battery bank knife switch in the electrical locker.
Method: Open the battery knife switch and lock. Confirm control voltage is absent at the relay panel.
Caution: The battery cannot be drained or removed for the job. It is the supply that stays live when everything else is isolated.
Main reservoir air, 140 psi, supplying brakes, sanders and the horn.
Method: Close the main reservoir cutout and bleed the reservoir to zero at the drain.
Caution: Stored main reservoir air operates the independent brake and the sanders without any electrical supply.
Shop jacks or drop table supporting the locomotive during traction motor removal.
Method: Do NOT isolate. Confirm all four jacks are rated, synchronised and bearing before the truck is rolled out.
Caution: Isolating the shop jack supply mid-lift strands the locomotive part-supported.
Pit lighting and ventilation under the shop track.
Method: Do NOT isolate. Confirm pit lighting and extraction are running before anyone enters the pit.
Caution: Traction motor work happens from the pit. Isolating pit services to lock the locomotive puts the crew in the dark.
What your site must supply
This example is structurally complete and factually generic. The things below are the things only you can know — and they are exactly what makes a procedure yours.
- Your own asset and isolation-point tag numbers. The tags shown are illustrative and refer to equipment that does not exist.
- The actual location of every disconnect, valve and vent on your equipment.
- Measured stored-energy magnitudes and the dwell time required to dissipate them.
- Your verification method for each point, and who is authorised to perform it.
- Any additional energy sources present on your equipment and absent here.
Author this properly, once
Setyr holds procedures like this as living documents — bound to real isolation points, with lock registries, group lockout, person-in-charge custody and periodic review built in.