Bidirectional running

[whole diary]

[eightf48544]

Don't forget that in power signalled areas the point motors have an integrated FPL^▸ (Facing Point Lock). So so long as the signalman has full detection both ways  then it's safe to run over them in the facing direction. There are also usually indivdual point switches so the that each point can be changed by itself rather than when it's part of the route being set. The interlocking still apllies so it should be safe to make the moves with pasengers on board.

Detection is very sensitive as I know from experience on a private railway where we have a point motor. We lose detection with the slightest maladjustment. If they are not track circuit failures then signal failures are often loss of detection on points. 

[bobm]

There were delays at Swindon at the weekend after the signaller lost detection on a set of points.  When staff on the ground inspected them, they found a crushed drinks can was the culprit.

[SandTEngineer]

Don't forget that in power signalled areas the point motors have an integrated FPL^▸ (Facing Point Lock).

The WR were very good at not providing FPLs in the point machine on trailing points without a signalled movement in the facing direction over them.  Quite a few sets still around like that  

....and just to clarify a couple of points ( ):

Bi-Directional signalling is that which allows two direction running on the same line within station limits.

Reversible signalling is usually between two distinct spaced out station limits.  In the 'old' days we used to call this SIMBIDS (Simplified Bi-Directional Signalling) which had no, or very few intermediate signals for the reversible direction or FULLBIDS (Full Bi-Directional Signalling) which had intermediate signals parallel to every normal direction signal on the adjacent line.  NR^» (Network Rail - home page) don't allow us dyed in the wool S&T^▸ (Signalling and Telegraph) Engineers to use those terms any more

[eightf48544]

Don't forget that in power signalled areas the point motors have an integrated FPL^▸ (Facing Point Lock).

The WR were very good at not providing FPLs in the point machine on trailing points without a signalled movement in the facing direction over them.  Quite a few sets still around like that  

That's very interesting S&T^▸ (Signalling and Telegraph) I thought the FPL was an integral part of the machine. Presummably it saved a few pounds buying them intially. I can't see it saving much in maintenace as it's a pretty robust piece of metal  and you still have to have full detection.

There were delays at Swindon at the weekend after the signaller lost detection on a set of points.  When staff on the ground inspected them, they found a crushed drinks can was the culprit.

I remember being told by an S&T engineer at Manchester London Road that they could get it set to detect a cigarette paper between the rails. Probably an exaggeration to impress young railwaymen  but not far short of the mark.

[Worcester_Passenger]

Bi-Directional signalling is that which allows two direction running on the same line within station limits.

Reversible signalling is usually between two distinct spaced out station limits.  In the 'old' days we used to call this SIMBIDS (Simplified Bi-Directional Signalling) which had no, or very few intermediate signals for the reversible direction or FULLBIDS (Full Bi-Directional Signalling) which had intermediate signals parallel to every normal direction signal on the adjacent line.  NR^» (Network Rail - home page) don't allow us dyed in the wool S&T^▸ (Signalling and Telegraph) Engineers to use those terms any more

Those strike me as quite sensible descriptions (it does what it says on the tin) - what do you have to describe these as nowadays?