Hold or Divert a Goods Train during a B-C Block
At 14:00, a loaded goods train G1 is at A with a crew that signed on at 06:30. It must reach D. The normal route A-B-C-D is 150 km and is booked at an average of 37.5 km/h. The B-C section is blocked for engineering work from 15:00 to 18:00, and the loop at B is occupied by engineering material, so G1 cannot be stabled there. The alternative route A-E-D is 210 km, but a temporary speed restriction limits the average to 35 km/h. The crew's permitted duty is 10 hours, extendable to 11 hours only with control approval and the crew's consent. A relief crew can reach A at 16:30 or E at 18:00. G1 is within load at 1,800 t. The next passenger train is due at A at 15:10 and must not be delayed. You are the section controller. The station master at A asks whether to hold G1 for the block or divert it, and whether the original crew can work either option.
1. Calculate the earliest legal arrival at D under (a) holding for the block and (b) diversion, assuming the original crew. Show your working.
Read the worked answer
Normal route: 150 km at 37.5 km/h equals 4.0 hours. G1 cannot enter B-C until 18:00, so if held at A it would arrive at D at 22:00. The original crew signed on at 06:30, so duty would be 15 hours 30 minutes, which is illegal. Diversion: 210 km at 35 km/h equals 6.0 hours. If G1 left A at 14:00, it would arrive at D at 20:00, giving 13 hours 30 minutes duty, also illegal. Therefore neither option is legal with the original crew. The calculation also shows that diversion is not a shortcut: the extra 60 km at the lower average speed takes two hours more than the normal route.
2. If relief is arranged at A, what is the earliest legal arrival, and what should be done with G1 before 16:30?
Read the worked answer
With relief at A at 16:30, G1 still cannot pass B-C until 18:00. The normal route then takes 4.0 hours, so arrival at D is 22:00. The relief crew would have 5 hours 30 minutes duty, which is legal. Diversion with the relief crew at 16:30 would take 6.0 hours and arrive at 22:30, so holding for the block is earlier. Before 16:30, G1 should be stabled in a loop or siding at A, not left on the running line, and the 15:10 passenger train must be cleared first. Do not give G1 line clear while the passenger is still to run. Arrange the relief crew, record the handover, and keep the original crew available only for rest.
3. What if relief at A is delayed until 18:30? Recalculate and decide.
Read the worked answer
If relief at A arrives at 18:30, the normal route gives departure at 18:30 and arrival at D at 22:30, with 4 hours duty for the fresh crew, which is legal. Diversion at 18:30 would take 6.0 hours and arrive at 00:30, which is later and operationally worse. The original crew still cannot work either option: diversion at 14:00 would have produced 13 hours 30 minutes duty by 20:00, and waiting would produce even more. The decision therefore remains to hold G1 at A, clear the passenger train at 15:10, and run G1 on the normal route as soon as the block lifts and the relief crew is available.