Level crossing timings

[jopsuk]

On my way to work (cycling) this morning, I was running a bit earlier than usual. I got to the Granham's Road CCTV Level Crossing just after the gates came down. Usually, as I'm coming down the cycle path by the railway (not shown on that image- old pictures!) the half seven service to Stansted storms past me, so I was kind of expecting this. After a minute or two, looking north I spied a trin movement. It didn't quite look right to me, and this was rather confirmed when I saw a FCC service heading off down the Royston line. Several minutes later, the Stansted service thunders through.

Now, when that FCC service was taking the other line, no movement through the crossing could have been possible- northbound, there's no signal between the crossing and junction. Surely the barriers didn't need to be closed quite so early? How long before a train approaches must CCTV crossing barriers be lowered? I assume linespeed is a factor- think it is about 80-90mph for trains on the route through Shelford.

Didn't make me late for work or anything, it's just a little bit annoying being stopped like that.

 

[Mojo]

Now, when that FCC service was taking the other line, no movement through the crossing could have been possible- northbound, there's no signal between the crossing and junction. Surely the barriers didn't need to be closed quite so early? How long before a train approaches must CCTV crossing barriers be lowered? I assume linespeed is a factor- think it is about 80-90mph for trains on the route through Shelford.

Correct me if I'm wrong, but I think CCTV crossings are interlinked with the signals, so the barriers will come down to ensure the train driver always sees a green signal.

 

[mumrar]

You have to consider other safety precautions which may be in operation, the crossing may be put down incase of a SPAD by a northbound train. In several places there are signals protecting junctions, but if the line is blocked a train is actually held one signal in the rear of the signal that protects the movement. Trains travelling southbound through Northfield are a prime example. If a cross-city train at Longbridge is either shunting or moving on to the fast for Redditch, a train on the fast from Kings Norton will be held at the signal at Northfield, not at the protecting signal at Longbridge.

 

[Ploughman]

A lot of the problems with drivers etc jumping crossings is down to length of time between barriers down and train arriving.
With AHB crossings I think these have the shortest time delay with about 25 seconds before train arrives.
On the York - Scarborough at Strensall with the CCTV crossings it is frequently 5 mins before train passes. With 3 crossings in the village it causes a lot of traffic delay.
Is this because the signalling needs to show a constant aspect to the driver?
Or because it is being passed on to the next block.
Is there any way of reducing the delay or would it need additional signals to be provided?
The foot crossing at Sherburn in Elmet station is another long delay location.
10 minutes has been noted. Is this due to high line speed and slow freight being predominant?

When the Merseyrail service to Southport was resignalled the delay time increased when manned boxes were withdrawn. That was a lot of crossings as well.

 

[O L Leigh]

This section of line is controlled by Cambridge PSB, but Cambridge station is controlled by a different workstation than Shepreth Branch Junction. Therefore there is a certain amount of scope for a mix-up, especially if either the FCC or AXC service(s) had been delayed departing Cambridge resulting in them leaving in a different order than expected.

There is nothing due northbound at this time of the morning. There is an 0716 departure from Shelford but then nothing until the 0721 AXC service from Stansted comes tearing through more than half an hour later.

O L Leigh