Naughty Naughty.....?

The location is Bromley-by-Bow, and like adw said, both flags can be raised to overcome traction defects, according to DD. The caveat is that the Line Controller must be informed before doing so, as running with both flags up causes the nice man with the letters 'DMT' on his jacket to show up.

i know one reason is that the signalling overlaps east of bromley - by - bow most of them were never designed for 60mph (d stock top speed) and speaking to a train tech a while ago he says with the weak field flag up it does cause the motors to arc occasionly so this is the reason why it has always been not allowed in the sub surface parts. but in passenger service the only places i know where you would get anywhere need this speed if used would be east ham - barking eb and both roads elm part - dagenham east.