The Kent History Forum
Travel and Transport => Railways => Topic started by: John Walker on October 04, 2023, 03:10:16 PM
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OFFDN sign on platform. I've noticed this large sign when waiting for trains. Can anyone enlighten me as to what it means. I'm guessing the DN might mean Down Line but not sure about the OFF part.
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I'd guess John that it is a repeater for the main signal which will either be ON DN or OFFDN so that station staff/guards can see on a curved platform. Just a guess though.
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And a good guess it is too MartinR. Exactly it’s purpose, as a repeater of the state of the platform starter.
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Thanks for the replies. I'm being a bit thick here. This one is on a straight platform with clear views along the track in both directions.
By main signal does that mean the signal that allows/prevents the train leaving the station? Also, what is meant by the platform starter.
This is all new to me.
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The starter signal is usually at the end of the platform and it gives the train clearance to leave the station.
It maybe on a straight, but the rest of the station furniture may mask the signal from the train guard. Footbridge, platform canopy that sort of thing.
Where is this John?
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The indicator in question is an 'off' indicator for the use of platform staff, it is lit when the signal authorising movements from the platform is showing a proceed aspect.
Platform staff may only give the 'right away' signal to the train guard or driver when they are sure that all the train doors are closed and passengers are clear of the train and the starting signal authorising movements from the platform is showing a proceed aspect (or is 'off').
The 'right away' signal may be given by either a hand signal to the train crew or by means of a plunger operated 'RA' indicator on the signal itself.
In Driver only operated areas, the starting signal may also be fitted with a 'CD' (close Doors) indicator which may be operated by the platform staff at any time regardless of the aspect displayed by the signal.
Johnfilmer is correct about platform furniture obscuring the signal aspect from the platform staff and to this may be added passengers if the station tends to have busy periods.
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The starter signal is usually at the end of the platform and it gives the train clearance to leave the station.
It maybe on a straight, but the rest of the station furniture may mask the signal from the train guard. Footbridge, platform canopy that sort of thing.
Where is this John?
Thanks for the info. This one was Canterbury East.
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The indicator in question is an 'off' indicator for the use of platform staff, it is lit when the signal authorising movements from the platform is showing a proceed aspect.
Platform staff may only give the 'right away' signal to the train guard or driver when they are sure that all the train doors are closed and passengers are clear of the train and the starting signal authorising movements from the platform is showing a proceed aspect (or is 'off').
The 'right away' signal may be given by either a hand signal to the train crew or by means of a plunger operated 'RA' indicator on the signal itself.
In Driver only operated areas, the starting signal may also be fitted with a 'CD' (close Doors) indicator which may be operated by the platform staff at any time regardless of the aspect displayed by the signal.
Johnfilmer is correct about platform furniture obscuring the signal aspect from the platform staff and to this may be added passengers if the station tends to have busy periods.
Thanks for the info. I never knew it was so complex.
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From my days as a guard on the Sittingbourne and Kemsley Light Railway:
1) The driver obtains the token (or ticket) for the section ahead. Not normally needed in mainline practice today as I understand.
2) The driver shows the token/ticket to the guard.
3) The starting signal is cleared¹. This does NOT permit the driver to start, merely tells him that the section ahead is clear.
4) The "Right away" is given by the station staff TO THE GUARD. As Stewie says, it may be a plunger, a hand signal (face the guard, whistle and raise your hand above your head) or by a paddle with a red face and a green or white face.
5) When the guard is happy, then he signals to the driver, traditionally by green flag, today by buzzer/bell.
6) Now the driver can start and drive to the next scheduled stop, stop signal, or signal from the guard (though the latter is only for abnormal circumstances of course).
Heritage lines may follow an older style, but must comply with rulebooks approved by the inspectorate. One job before being passed as a guard is to learn the rulebook and be tested on it, just like main line. Mainline practice uses computerised signalling and some of the steps above may be combined.
It may seem strange that both a token and a signal are needed, but they demonstrate slightly different things. The token shows that the loco is the only one permitted in the block whereas the signal shows that the block is physically clear, for instance crossing gates are locked open for the train.
¹This may not apply on certain short lines where there is only one block.