Power Supply (Signalling & Operation)

All the freightliners in the Carlisle 79-80 timetable are worked by pairs of AC electric locos except those that are diesel hauled via the Newcastle line. I'm very well aware of the power of pairs of AC electric locos working in multiple on heavy freight services as I dealt with them between 1990 - 1994 whilst working at Liverpool Street Regional Control office with pairs of Cl.86s working between Willesden - Ipswich/Parkeston - Willesden. Also there are pairs working Ravenscraig - Dee Marsh steel trains. What people probably aren't aware of is the exceptional power drain in the 25Kv overhead traction current supply when you have a pair of AC locos working hard. You'd be lucky to get 80mph from a class 1 express worked by another AC loco in the same section as a pair of AC locos working hard on a freightliner or heavy freight train, such was the power drain on the overheads. Even EMUs also suffered the same low power performance if caught in the same section. Cl.87s having 5,000 horsepower, but they all tended to suffer from wheelslip due to their weight being light compared to heavier diesel locos. During the early 1990s any freightliners working through Colchester around midday the rear loco had to drop its pantograph between certain neutral sections either side of Colchester station as the national grid couldn't cope with the exceptional power drain from the overhead wires. If a freightliner worked by a pair of Cl.86s on full power went through the affected sections without dropping the 'pan' on the rear loco the whole of Colchester would get blacked out.

Greenhill Upper Junction, 22 March 2009.

Greenhill Upper Junction, 22 March 2009. Points 125C failed to move Reverse when commanded by the route setting and when keyed Reverse by the signaller, and in both cases 125 indicated Reverse despite 125C being normal on the ground.

In very very brief summary, there was a wiring error that meant that 125C merely needed to be locked and detected in either position (125A and 125B needed to be locked and detected in the correct position). And then track workers left points 125C in manual, rather than interlocking, mode.

Thankfully it was that way round and the points were trailing to the first train to hit them in the wrong position (at 64 mph). If "normal" and "reverse" had been swapped in the above description, 125C would have been facing to a train doing 100 mph.