Morning,
I wonder if any one can shed any light ont he following:

Liverpool Street's CIS was advertising un specific delays;

Just after 06:35 on the East bound Central line at Liverpool Street
waiting for the train on the platform the CIS was sat there saying 1
min... After proabley 4 Min a train came crawling into the platform.

The signal at the end of the platform was showing danger.

The train crawled round the corner into the platform (Much slower then
usual) and I noticed that the front right (As the driver sits) yellow
light was flashing. (Between the white running lights, and red tail
lights)

Got on the train, it sat there a moment (For the signal to clear?)
then off we went towards Bank at the usual speed.

I didn't notice if the train was under full ATO or if it was being
'driven' as it came into Liverpool Street.

Any ideas ? The best I could come up with was something along the
lines of either an ATO block failure, or something like that.

Thanks in advance.