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Setting routes across manual level crossings (LCs)

You are here: Home > Forum > General > General questions, comments, and issues > Setting routes across manual level crossings (LCs)

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Setting routes across manual level crossings (LCs) 15/04/2014 at 03:57 #58905
Hawk777
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386 posts 		If I had to guess, I’d say no reaction is necessary:

  • When the signal goes blank, the next signal in rear goes red, protecting the LC.

  • If the signal were originally non-red, then a route must have been set from it, which means the LC must have been closed.

  • If a train were closely approaching the signal and the signal were originally red, then the train must have passed a yellow signal and be driving slowly, ready to stop short.
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Setting routes across manual level crossings (LCs) 15/04/2014 at 07:57 #58912
AndyG
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1834 posts 		Whilst visiting the Cambridge PSB on Saturday, it seemed the method used by both signallers on the left hand panel was:-
1) switch on camera;
2a) start lower sequence;
2b) keep finger hovering over the 'Stop' (lower sequence) button;
3) confirm crossing clear;
4)set route(s) over crossing.

Apparently the reason for step 2b) is down to the level of user abuse whilst lowering the barriers.

Many thanks to Clive for arranging the visit, and the staff for being so accommodating.
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either.
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The following user said thank you: maxand
Setting routes across manual level crossings (LCs) 15/04/2014 at 14:01 #58925
Firefly
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521 posts 		Ok, I'll do my best to tie up some of the loose ends.

Quote:
Less worryingly, how would a level crossing react to a failed red lamp, if at all?
When we say that a signal should be at Red and free of approach locking (ARAFOAL) we only prove that the signal controls are at Red. If a red lamp fails it will hold the signal in rear at Red but won't effect the crossing.

As Hawk777 has correctly noted:-
Quote:
If a train were closely approaching the signal and the signal were originally red, then the train must have passed a yellow signal and be driving slowly, ready to stop short.

And a driver will treat an unlit signal as a Red. The signal would have AWS so the driver would get a warning that he's approaching a signal even if it's dark/foggy. Finally if he does miss the unlit signal it will be at low speed and the crossing "Run By" controls would initiate the crossing sequence automatically as soon as the train passes the signal causing the barriers to lower (Regardless of what cars may be on the crossing)

Quote:

the original question was why not allow the barriers to be raised when a route was set but the protecting signal was still red, which would not akin to cancelling a signal because the signal was already red to start with.
As Steve has pointed out we have different rules for Auto Raise than we do for Manual Raise.

When in Auto Raise we allow the barriers to raise once a train has been proved to have traversed the crossing and the signal has returned to red. We do not need to cancel the route when in Auto Raise. (Partly because the signal could have an 'A' button allowing it to work automatically, or it could be a mechanical box and levers don't replace themselves)

Manual Raise on the other hand needs to account for all circumstances.

This must include a normal situation where a train gets a clear signal and traverses the crossing.
It must include a failure situation whereby for some reason the signal doesn't clear and the signaller talks the train past the signal at red.
It must also include the signal being replaced to danger in front of a train, the train stopping before the signal and the approach locking timing off.
It must also include the signal being replaced to danger in front of a train, the train failing to stop and passing the signal. (in which case the crossing would remain locked down until the train has continued its journey)
It must include a train entering onto the crossing, stopping, reversing etc

Just proving the signal is showing red does not achieve all of the above requirements, and neither does just using track circuits. The only proper way is to prove that the route locking is completely normal. Route locking normal (no white lights) proves:-
Signal Aspect Controls are at Red
Signal Route Controls are Normal
Approach Locking is Free
No Trains are within the route.

If you've satisfied the above then it must be safe to raise the barriers.

Hopefully this makes some sense.
Last edited: 15/04/2014 at 14:05 by Firefly
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The following user said thank you: guidomcc
Setting routes across manual level crossings (LCs) 19/04/2014 at 08:31 #59098
maxand
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1637 posts 		On a simpler note and from a SimSig player's point of view, perhaps the best reason for always lowering the barriers before setting a route is that on some manual LCs one can't set a route across the LC until the barriers are down! For example, the Pinhoe, Topsham and Paignton LCs in the Exeter sim.

Likewise, their barriers cannot be raised until any routes set across them are released.

So if one isn't sure whether or not the LC allows the route to be set before lowering the barriers, trying to do so wastes precious time.
Last edited: 19/04/2014 at 08:32 by maxand
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