OPO and countdown markers

I'm drunk at the moment, so I appologise for any misunderstanings etc, but if I understand tubeprune's question correctly he is (partly?) asking about the white on turquoise (I think) car-length markers beyond the end of the platform seen for example in this photo I took at Dagenham Heathway.

If so, this thread seems apropriate to my question - are these based on the actual lengths of the cars or a theoretical average length of cars that use the line? Will they need to be changed when the S stock starts running in passenger service as I guess (I don't rememeber and am not sober enough to find out) they are not the exact same length as A, C or D stock cars?

No - they were converted to alarm only - in the case of D stock it wasn't a major problem to change, but C and A stocks were converted as part of the refurbishment. Not sure of the exact date that D stock went to alarm only.


Initially exclamation marks were provided about a trains length from the platform - the intention being that if the driver could see a marker when the alarm sounded, the train should be stopped, otherwise the train should continue to the next station. One problem with this is that in some cases it was not possible to see the exclamation mark as you left, due to curvature etc. Although some stations were provided with additional markers, not all were. Leaving Aldgate Inner Rail was a classic example - the only marker wasn't visible by the driver until you were almost at it, so taking the rules literally, if the Pass Alarm was operated as you left, you would continue until you were almost completely out of the platform before stopping the train
I believe the sub-surface stocks were converted first, and 1999 is about the right time, and I believe (but stand to be corrected) that the 92s weren't converted to have the pedal release quite a bit later. Not sure about other stocks.


I believe the major factor in the change was the incident at Leicester Square on the Picc line, where someone fell between the cars, a Pass Alarm was operated, but by the time the driver was able to respond the train was already entering Covent Garden, so he continued into the platform. LUL then decided that it was preferable to change the scenario from 'Pass Alarm; driver reaction time; apply brakes if in station limits' to 'Pass Alarm; brakes apply; driver reaction time; continue if NOT in station limits.
Whilst I was H&S rep at Edgware Road, from 1993-95, I did suggest that using car numbering marks would be preferable to the exclamation marks, as you could then have different marks according to the stock, as well as the ability to determine the point at which the alarm was operated (ie how far out of the platform the train was when the alarm was operated). Part of my thinking of this was related to the Hounslow East incident where an elderly lady fell under a train as it left the station, having had her coat caught in the doors. The train was stopped by the Pass Alarm, but no-one was sure how far the train had travelled when the alarm was operated.

Hope this info helps

Brake Override Device.

It was done on the C stock in 1998/9

I agree. The temporary speed restriction boards fixed to sleepers are often hard to see properly. Snow is the worst problem, though not often encountered!

The spacing of the countdown markers seems weird to me; they look to be placed closer together as the car number increases.

Some are placed closer together; 1-2 etc are full cars lengths, that from 5-6, 6-7 and 7-8 are around half car lengths; this is to allow for at least one set of doors to be in the platform on the last car....

Well, I'm glad someone understood my explanation.... And if you pass the 'Exclamation Mark' after the count up numbers have finished, counting up... it means no doors are in the station, so carry on to the next one, 'where help can be given more easily'...

You are correct the countdown (should be up) markers did replace the exclamation markers which were in every platform tube, sub surface and surface.

But like a lot of other remnants on the combine they are technically redundant.