"Ken" wrote in message
...

On a related note, my uncle used to drive Circle and H&C services and
he claimed that the A stock used to cause service problems as it was
'slower' than the other stock over the northern part of the Circle. By
'other stock' he meant the CO/CP that was in use at the time.

Although the acceleration of the "A" stock is slightly lower than the "C"
stock, the main problem is that because it is longer it causes more track
circuits to remain down for longer, causing the signals to remain at danger
for longer.