Single-Line Block Instrument Failure with Three Trains
At 02:10, you are the section controller for the single-line absolute-block section Kalyanpur (KYN)-Ratanpur (RTP), 14 km, with a rising gradient of 1 in 100 from KYN to RTP and no intermediate block signalling. The block instrument has failed; only the control telephone works. Train 12345 (passenger, 18 coaches) is ready at KYN to proceed to RTP. Train 12346 (loaded goods, 42 wagons, brake power 6,800 t) is ready at RTP to proceed to KYN. A departmental train 56789 carrying engineering material is expected at RTP at 02:40 from the rear. Fog patches reduce visibility to about 200 m. The adjacent double-line section has an engineering block until 03:00, so diversions are not possible. Both station masters ask for line clear. You must decide how to work the section, which train to admit first, and what instructions and records are needed. No train may be allowed to enter the section until the previous train has arrived complete.
1. What manual block-working arrangements should you institute, and why must only one train be in the section at a time?
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Treat the failed instrument as a manual block working. The station masters must exchange private numbers for every line clear, use paper line-clear messages, and record the time, train number, and names of the officials. The receiving station must not grant line clear for another train until the previous train has arrived complete with tail lamp and guard, and the station master has advised arrival. Only one train can be in the section because the absolute-block safeguard has been lost, there is no intermediate block signalling, and the single line has a rising gradient and fog. Two opposing trains would create a real head-on risk. I would also issue a caution order for fog and the gradient, advise drivers to proceed at restricted speed, and keep 56789 at RTP until the passenger and goods have cleared. The engineering block on the adjacent section removes any diversion option.
2. Which train should be admitted first, and what operating factors support that choice?
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Admit 12345, the passenger, first from KYN to RTP. It has higher passenger priority, and holding it would increase public delay and possibly affect crew hours. It will climb the 1 in 100 gradient toward RTP, so it is better to start it before fog thickens rather than stop it on the grade. The loaded goods 12346 is at RTP and would run downhill toward KYN; it is easier to hold and restart at RTP than the passenger on the climb. The goods also has a heavy load, but its brake power and descending direction reduce the immediate risk. After 12345 arrives complete, admit 12346, then deal with 56789. If 12346's crew were already near the duty limit, that would be a reason to review the order, but on the facts given the passenger should go first.
3. What records, authorities and caution orders must be completed, and how would you handle the engineering train?
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Record the instrument failure time, the names of both station masters, every private number exchanged, line-clear times, arrival-complete times, caution-order numbers, and the speed restriction imposed. Issue written authority for manual block working and caution orders for fog and gradient; if visibility at the level crossing is poor, arrange fog signalmen. For 56789, do not grant line clear merely because it is departmental. Confirm its load is secured, treat it as a goods train, and admit it only after 12345 and 12346 have arrived complete and the section is proven clear. Because the engineering train is expected from the rear at RTP, it must wait until the opposing movements are finished. Inform control of each step and log any deviation from the timetable.