Approach Control at turn-outs

[Welshman]

I believe the turn-out from the down line to the platform loop approaching Rhyl from Prestatyn is approach-controlled, as I think the line speed is 75mph and the turn-out 35mph.

This means every train accelerates to line speed out of Prestatyn, then prematurely slows down for the approach-controlled turn-out, then accelerates again to get into Rhyl down platform.

This confuses passengers, who've been informed by the train's p.a that they are now approaching Rhyl just as the train's slowing for the approach-control, so they're walking through the aisles with luggage, or standing in the vestibules as the train slows, then speeds-up through the turn-out.

In addition to possible injury to passengers there's the cost of unecessary braking and accelerating.

The same thing happens again further down the line for trains stopping at Abergele. Here, I think the turn-out speed is even more limiting. And I've no doubt there are other examples on the network. Would there not be a good case for remodelling the turn-out to allow the speed to be increased to that appropriate to a train slowing gradually to the station stop?

An initial expense that could save in the long-term with regards to costs to the environment and confusing/danger to alighting passengers.

 

[mumrar]

I believe the turn-out from the down line to the platform loop approaching Rhyl from Prestatyn is approach-controlled, as I think the line speed is 75mph and the turn-out 35mph.

This means every train accelerates to line speed out of Prestatyn, then prematurely slows down for the approach-controlled turn-out, then accelerates again to get into Rhyl down platform.

This confuses passengers, who've been informed by the train's p.a that they are now approaching Rhyl just as the train's slowing for the approach-control, so they're walking through the aisles with luggage, or standing in the vestibules as the train slows, then speeds-up through the turn-out.

In addition to possible injury to passengers there's the cost of unecessary braking and accelerating.

The same thing happens again further down the line for trains stopping at Abergele. Here, I think the turn-out speed is even more limiting. And I've no doubt there are other examples on the network. Would there not be a good case for remodelling the turn-out to allow the speed to be increased to that appropriate to a train slowing gradually to the station stop?

An initial expense that could save in the long-term with regards to costs to the environment and confusing/danger to alighting passengers.

The costs would be prohibitive, and in a lot of areas where platform lines exist purely as loops, having a calmer entrance/exit angle will mean shortening the platform or widening the track bed. More expense.

It's very difficult to avoid confusing some passengers, but I don't see where the danger you mention is? Please explain that better.

Also worth factoring in that the faster the crossover the bigger it is (length) and the more maintenance will be required on it than a lower speed item. In most cases this would save less than 30 seconds, so it would be a waste of money especially at these prudent times.

 

[Welshman]

The costs would be prohibitive, and in a lot of areas where platform lines exist purely as loops, having a calmer entrance/exit angle will mean shortening the platform or widening the track bed. More expense.

It's very difficult to avoid confusing some passengers, but I don't see where the danger you mention is? Please explain that better.

Also worth factoring in that the faster the crossover the bigger it is (length) and the more maintenance will be required on it than a lower speed item. In most cases this would save less than 30 seconds, so it would be a waste of money especially at these prudent times.

The danger is of personal injury to passengers - walking down the aisle with heavy luggage or standing in the vestibules and then being thrown against others as the train unexpectedly accelerates and sometimes jolts through the turn-out.

Regarding this particular case at Rhyl, the turn-out is sufficiently outside the station to mean the platform would not have to be shortened, and there is plenty of space as other tracks have been removed.

I take your point about increasing costs, mumrar, and it would not be worth it if saving time was the only consideration. But my main concerns were the costs to the environment of unecessary braking and acceleration, and the comfort of the passengers.

 

[mumrar]

I can see what you're saying but you can only minimise risks of injury, you'll never irradicate them. If someone is a risk due to being stood up, there's little to be done. Whilst it's a very minor issue, there is far more pressing stuff for the network, such as electrification and other projects.

 

[Geezertronic]

You could apply that line of thought to any train service though. What about if you got up to go to the toilet and the train was slowing down and speeding up again? Same thing could apply.

The VT staff who work the aisles on the rollercoaster WCML South in particular seem to do well at not spilling stuff over the passengers

 

[Old Timer]

The danger is of personal injury to passengers - walking down the aisle with heavy luggage or standing in the vestibules and then being thrown against others as the train unexpectedly accelerates and sometimes jolts through the turn-out..

The speed of the turnout is designed so that there is no "jolt". A jolt indicates straight away either a maintenance (geometry ?) fault or the train is running into/out of the turnout above design speed.

When the S&C at South Yorkshire Jct at Doncaster was renewed some years back the speed was increased to 40mph. After a short period the switch rails starting to show signs of sidewear and it was discovered that Drivers were exceeding the speed limit because even above 40, the turnout was still smooth, the problem being however that the smooth ride was disguising the rapid sidewear on the switches. Once some speed checks were undertaken, the wear issue stopped.

Whilst a longer switch might ease the perceived problem, it will without doubt affect the positioning of the protecting signal (the higher the crossover, the longer it is). This will in turn impact upon signal spacing with signals to the rear, which in turn will impose absolutely ridiculous signal sighting rules that were knee-jerked in through media and Political pressure following Ladbroke Grove.

£250k for a new crossover suddenly becomes a bill of £1 million, or more.

Ridiculous rules and Standards are now driving Network Rail engineering back into the 1980s, as new UIC 60 S&C is being down-scoped to UIC54 or even 113 full depth in order to save money and remove the impact of Standards.

Like for like replacement of S&C which does not trigger new Standards is now the vogue I am told.

The real answer is to revisit, vigorously challenge, and remove over-cautious requirements which were driven by knee-jerk expediency following incidents, rather than being genuinely needed.

Sometimes the answer really IS to do nothing, sadly in the UK we are driven by a soundbite Media and Political lightweights, who push the "something must do done option" as a means of cheap personal gain, to the detriment of society generally.

 

[Welshman]

Thank you, Old Timer, for that informative reply.
I hadn't thought of it in the context of the knock-on effect on signal spacing along the line from Prestatyn.

 

[68000]

Surely the most cost effective answer is for the TOC to change when the PA comes in - ie after the train has taken the junction.

 

[asylumxl]

When the S&C at South Yorkshire Jct at Doncaster was renewed some years back the speed was increased to 40mph. After a short period the switch rails starting to show signs of sidewear and it was discovered that Drivers were exceeding the speed limit because even above 40, the turnout was still smooth, the problem being however that the smooth ride was disguising the rapid sidewear on the switches. Once some speed checks were undertaken, the wear issue stopped.

Bit OT, but what kind of speed were they doing over the switches?

Were the drivers disciplined?

 

[Old Timer]

Bit OT, but what kind of speed were they doing over the switches?

Were the drivers disciplined?

We measured them at up to 55mph, and yes I believe appropriate action was taken by the TOCs.

That said the approach to speed has changed fundamentally since then.

Nowadays it is apparantly getting harder to achieve designed turnout speeds because Drivers are tiptoing around like ballet dancers on ice, what with all these various driving "policies" that they can be sacked for infringing.

Not like here where Drivers are braking as they are running through the turnouts at design speed (80), because it takes them over 3km to stop at the other end of the passing loop. If they had UK style driving policies the job would simply shut down.

 

[The Planner]

Nowadays it is apparantly getting harder to achieve designed turnout speeds because Drivers are tiptoing around like ballet dancers on ice, what with all these various driving "policies" that they can be sacked for infringing.

Not like here where Drivers are braking as they are running through the turnouts at design speed (80), because it takes them over 3km to stop at the other end of the passing loop. If they had UK style driving policies the job would simply shut down.

This is very true, defensive driving causes us a lot of problems now. As policies evolve and when new signalling schemes come in, a lot of flexibility that was once there goes due to "modern signalling standards". Everything seems to get double red protection and incredibly harsh approach controls. Our biggest problems are that we dont find out we can't do something until after it has been put in and the trains are running !! the signallers dont know either until they try and do something and it won't work.

 

[RPM]

Drivers are tiptoing around like ballet dancers on ice, what with all these various driving "policies" that they can be sacked for infringing.

Ain't that the truth. I gather our next uniform issue will include tights and tutus.
--- old post above --- --- new post below ---

This is very true, defensive driving causes us a lot of problems now. As policies evolve and when new signalling schemes come in, a lot of flexibility that was once there goes due to "modern signalling standards". Everything seems to get double red protection and incredibly harsh approach controls.

We've got this problem on the approach to Aylesbury Vale Parkway. The track circuit that needs to be activated to give you the route into the platform is so short that you have to almost come to a stand at the red before it comes off, all to protect a 20mph turnout which you wouldn't be taking at more than 20 anyway because it is a dead end platform (and you've got both TPWS and ATP protection!)