"Following a series of transformer explosions, caused by damage to the transformer windings from backfires in the mercury arc rectifiers, the entire stock of Class 303s had to be hastily withdrawn from service after only a few weeks' service. Over the weekend of 17/18 December 1960 all 72 EMU sets were taken into strorage and the old steam-operated service was temporarily reinstated whilst urgent modifications were made. This also delayed the handing over of the Cathcart Circle service to electric operation."
External factors, but Rotherham Tram-Train had a major lorry incident on the first day of operation, IIRC
Hm. The class 155s had some fairly major issues (partly involving the doors maybe?) just after introduction on the Cardiff - Portsmouth’s.The Dutch Fyra/V250 trains didn't do too well and were all withdrawn within a few months. A few sustained quite severe damage to themselves just on their regular journeys from memory (partly due to snow/ice though).
There was also the one (478?) that was an insurance write-off after going for an unplanned swim in Scotland a few years back. Even that one returned to service.Lots of Neville Hill units had serious collisions in the first few years.
156468/490 collided in the tragic Ais Gill crash in 1995. The worst affected 524xx vehicles took a couple of years to repair.
156473 hit by a stolen JCB at Pudsey foot crossing.
156498 collided with 91019 at Holbeck Junc.
156483 collided with a RES 47 at Leeds west end and apparently had a slightly twisted frame but was still repaired.
156489 collided with a 60 at Crosby Garrett.
All badly damaged and all repaired. The 156’s are strong old units.