Signals and codes on departure

[crewmeal]

Just before a train departs I've seen signs and letters along with a green signal. For example what does 'off' mean? There are often other single letters that go with the off sign. Without wishing to sound stupid what do they all mean?

 

[Welshman]

Letters at the signal often indicate the route to be taken - for example, Fast line, Slow line, Line "A" or whatever.

The word "OFF" is often found near the rear end of the platform, where it acts as an indicator to station staff and the conductor/guard of the train. It is particularly helpful when the departing signal cannot be sighted from the rear of the train because of a curve, station structures, etc.

Station dispatchers/conductors are not allowed to give the departure signal to the driver unless the signal ahead is clear, and the word "OFF" informs them it is. If it were not clear, the sign will read "ON"

The words "Off" and "On" go back to the early days of signalling practice. Signals simply consisted of a wooden board horizontally across the track forbidding a train to pass. So the board was "on". When it was safe to proceed, the board was lowered, raised or removed, so the board was then "off"

Older railwaymen still sometimes refer to the "board being on or off" even with a modern colour-light signal.

I hope this has answered some of your queries.

 

[GB]

Along with the "On" and "OFF" indicators you will also usually see "CD" as an instruction to close the doors and "RA" for right away to denote station duties complete and train ok to proceed.

 

[crewmeal]

Thanks very much for that. A very interesting account, much appreciated.

 

[Tomnick]

On a pedantic point, the vast majority (possibly all?) of 'OFF' indicators will be extinguished when the associated signal isn't displaying a proceed aspect - I think some early ones had a separate 'ON' indication, but I've never seen one.

 

[The Colonel]

On a pedantic point, the vast majority (possibly all?) of 'OFF' indicators will be extinguished when the associated signal isn't displaying a proceed aspect - I think some early ones had a separate 'ON' indication, but I've never seen one.

My station's ones just show "OFF" and aren't illiminated when the signal is ON - I've never seen one which actually says ON, certainly not on the old Southern Region.

As an aside ANY signal not showing any indication is treated as exhibiting a danger aspect and must not be passed.

 

[craigwilson]

Along with the "On" and "OFF" indicators you will also usually see "CD" as an instruction to close the doors and "RA" for right away to denote station duties complete and train ok to proceed.

With "OFF" indicators you'll often see a direction of travel indicated if the line is bi-directional e.g. at my nearest station, Margate, you'll see "OFF UP" - indicating the signal is cleared in the "up" direction, i.e. towards London, and "OFF DN" for moves in the other ("down") direction.

At Ramsgate, where it is a terminus for routes from Victoria and Charing Cross, and all platforms are bi-di, then you'd always be exiting in the "up" direction. There, the indicators read "OFF FV" for moves in the Faversham direction (to Victoria), and "OFF MI" for the Minster direction (towards Charing Cross, both via Dover and Canterbury)

 

[ralphchadkirk]

As an aside ANY signal not showing any indication is treated as exhibiting a danger aspect and must not be passed.

Even a distant signal?

 

[swt_passenger]

Along with the "On" and "OFF" indicators you will also usually see "CD" as an instruction to close the doors and "RA" for right away to denote station duties complete and train ok to proceed.

'Usually' only applies in those areas where platform staff are dispatching with driver only operation though. There are still relatively large areas where you won't see CD/RA indicators at all, eg on SWT's network.

 

[Rich_D3167]

As an aside ANY signal not showing any indication is treated as exhibiting a danger aspect and must not be passed.

Not quite. A signal which is not displaying any aspect is treated as it's most restrictive aspect. In the case of a stop signal, that will indeed be danger, and should not be passed without the permission of the Signaller. In the case of a distant signal (which is incapable of displaying a danger aspect), the most restrictive aspect is caution, so therefore can be passed (being prepared to stop at the next signal, which will be a stop signal).

 

[Shimbleshanks]

Some 20-30 years ago, I remember a friendly guard on a Crewe-Manchester local pointing out with great amusement the indicator for the fast line platform at an intermediate station (it could have been Wilmslow) displaying 'F OFF'.

 

[TDK]

Even a distant signal?

You won't usually get a distant signal as a station starter and if you did there wouldn't be an off indicator so where is this relevent to the op?

 

[ralphchadkirk]

You won't usually get a distant signal as a station starter and if you did there wouldn't be an off indicator so where is this relevent to the op?

I presume you didn't read the excerpt I quoted?

 

[6Gman]

The words "Off" and "On" go back to the early days of signalling practice. Signals simply consisted of a wooden board horizontally across the track forbidding a train to pass. So the board was "on". When it was safe to proceed, the board was lowered, raised or removed, so the board was then "off"

Older railwaymen still sometimes refer to the "board being on or off" even with a modern colour-light signal.

I hope this has answered some of your queries.

I must be getting old! I still refer to the board being off; signalmen are still bobbies etc etc

 

[Railsigns]

More information on "Off" indicators and the like here:

http://www.railsigns.co.uk/sect22page1/sect22page1.html

 

[The Colonel]

Not quite. A signal which is not displaying any aspect is treated as it's most restrictive aspect. In the case of a stop signal, that will indeed be danger, and should not be passed without the permission of the Signaller. In the case of a distant signal (which is incapable of displaying a danger aspect), the most restrictive aspect is caution, so therefore can be passed (being prepared to stop at the next signal, which will be a stop signal).

Thank you for the clarification.

The Colonel