17.27 From Marylebone to West Ruislip slow

[pethadine82]

I often catch this service on different days of the week, and notice that when we get to the Chiltern depot area in Neasden the train decelerates rapidly, and crawls, and sometimes stops at Wembley stadium, but the doors don't open.

I cant work out why this would be as the previous train had left some time ago.
Does anyone know why?

 

[yorkie]

...the previous train had left some time ago....

only 3 minutes! That's not quite enough time for the 1724 to decelerate, call at Wembley, accelerate back up to line speed and still leave a sufficient gap for the train behind to get clear signals unfortunately.

However this is built into the timetable.

 

[455driver]

A 10 second look on realtraintimes shows that the 1724 Marylebone to Bicester north is only a minute in front after it makes its call at Wembley Stadium, if it loses a couple of minutes (as it has done today) then your train will pick up cautionary aspects, your Train will have a couple of minutes pathing allowance built into its running time..

 

[berneyarms]

A very good analysis from the two posters above.

A slightly longer than 10 second look at Realtimetrains shows that not only do you have the above, in fact you have a whole series of trains within 3 minutes of each other:

17:15 to Kidderminster (non-stop to Leamington Spa) - catches up with 17:02 to High Wycombe at High Wycombe (train immediately in front is 17:11 to Aylesbury via Amersham, so this train has a clear run from Neasden Junction).

17:18 to High Wycombe - Runs 3 mins behind 17:15 until Princes Risborough where it decelerates for Haddenham & Thame Parkway

17:21 to Banbury - Runs 3 mins behind 17:18 extending to 4 mins by Denham Golf Club - first stop is Beaconsfield

17:24 to Bicester North - Runs 3 mins behind 17:21; First stop Wembley Stadium and then Denham - gap extends to 5.5 mins by West Ruislip

17:27 to West Ruislip - Runs 3 mins behind 17:24; Has 2 mins added to the schedule between Neasden South Jctn and Wembley Stadium to allow for the train in front stopping at Wembley Stadium, and then has a first stop at Sudbury & Harrow 4.5 minutes behind the train in front.

So....if any one of those trains has a delay there is going to be a knock on to the services behind. Having five trains leaving one behind the other within 3 minutes of the previous one, but in particular with the second last having an extra intermediate stop, it is going to be tight at the best of times (even with the pathing allowance)!

 

[The Planner]

The 2 minutes pathing is approaching Wembley Stadium, the allowances apply approaching the timing point below it, not the one they are next to. It would be odd to have it approaching Neasden South. The Chiltern peak timetable has always been tight, noticeable by the split use of engineering allowance to keep trains apart which is a little bit naughty.

 

[berneyarms]

The 2 minutes pathing is approaching Wembley Stadium, the allowances apply approaching the timing point below it, not the one they are next to. It would be odd to have it approaching Neasden South. The Chiltern peak timetable has always been tight, noticeable by the split use of engineering allowance to keep trains apart which is a little bit naughty.

Yes - sorry - my mistake!! Thanks for the correction. I've edited my post above.

Yes - it's always interesting to look at the righthand columns for additional allowances in timetables, to see where a little bit more resilience has been added!

 

[The Planner]

It is all meant to be there, but not necessarily in the locations shown and engineering allowance is normally in whole minutes. Performance time is the only allowance that is purely resilience/padding and that is a TOC request, all the others are there for a reason. RTT doesn't show adjustment allowances for junctions etc..

 

[Class 170101]

The 2 minutes pathing is approaching Wembley Stadium, the allowances apply approaching the timing point below it, not the one they are next to. It would be odd to have it approaching Neasden South. The Chiltern peak timetable has always been tight, noticeable by the split use of engineering allowance to keep trains apart which is a little bit naughty.

But NR have obviously authorised it otherwise the train shouldn't be accepted by them. I am afraid I wouldn't be surprised if there are other examples like this around the country.

 

[The Planner]

Of course we authorised it, it is just bending the rules as they specify an amount of time approaching a location, normally that is where you put it. We are the ones at risk for the delay minutes as we said yes to it. Like you suggest there are plenty of examples where we and the TOCs play games with it, that's where experience comes in.

 

[Cherry_Picker]

A slightly longer than 10 second look at Realtimetrains shows that not only do you have the above, in fact you have a whole series of trains within 3 minutes of each other:

17:15 to Kidderminster (non-stop to Leamington Spa) - catches up with 17:02 to High Wycombe at High Wycombe (train immediately in front is 17:11 to Aylesbury via Amersham, so this train has a clear run from Neasden Junction).

From bitter experience I can tell you that the 16:57 Marylebone - Gerrards Cross is more likely to hold up the Kidderminster service, that one goes round the loop at South Ruislip and arrives at Gerrards Cross two or three minutes before the 17:15 is booked to pass through at 100mph. The driver then has to check the train is empty before the trains forms 5G72 (Gerrards Cross to Gerrards Cross turnback sidings) and a tight timing suddenly becomes incredibly tight and as you said, obviously this will have a knock on effect on all following services. As 5G72 has to cross the up to get into the sidings it can put a small delay on 2H71 (17:20 HWY-MYB) too. It's a capacity issue which is very difficult to solve unless you throw an awful lot of money at it eg; rebuild the down side of Gerrards Cross station with a south facing bay, install the bay platform at Denham and withdraw the Gerrards Cross terminating service to Denham (which would be very unpopular) or reinstate through lines at Beaconsfield and extend the Gerrards terminating service to Beaconsfield which would require a timetable recast. I'm not sure it would do too much damage to diagramming considering how long trains can spend in that turnback at Gerrards Cross.

 

[Nym]

From bitter experience I can tell you that the 16:57 Marylebone - Gerrards Cross is more likely to hold up the Kidderminster service, that one goes round the loop at South Ruislip and arrives at Gerrards Cross two or three minutes before the 17:15 is booked to pass through at 100mph. The driver then has to check the train is empty before the trains forms 5G72 (Gerrards Cross to Gerrards Cross turnback sidings) and a tight timing suddenly becomes incredibly tight and as you said, obviously this will have a knock on effect on all following services. As 5G72 has to cross the up to get into the sidings it can put a small delay on 2H71 (17:20 HWY-MYB) too. It's a capacity issue which is very difficult to solve unless you throw an awful lot of money at it eg; rebuild the down side of Gerrards Cross station with a south facing bay, install the bay platform at Denham and withdraw the Gerrards Cross terminating service to Denham (which would be very unpopular) or reinstate through lines at Beaconsfield and extend the Gerrards terminating service to Beaconsfield which would require a timetable recast. I'm not sure it would do too much damage to diagramming considering how long trains can spend in that turnback at Gerrards Cross.

Or, just pay platform staff to tip out the train and clear it for the driver?

 

[455driver]

Or, just pay platform staff to tip out the train and clear it for the driver?

The railways are trying to reduce staffing levels not increase them!

 

[67018]

From bitter experience I can tell you that the 16:57 Marylebone - Gerrards Cross is more likely to hold up the Kidderminster service, that one goes round the loop at South Ruislip and arrives at Gerrards Cross two or three minutes before the 17:15 is booked to pass through at 100mph. The driver then has to check the train is empty before the trains forms 5G72 (Gerrards Cross to Gerrards Cross turnback sidings) and a tight timing suddenly becomes incredibly tight and as you said, obviously this will have a knock on effect on all following services. As 5G72 has to cross the up to get into the sidings it can put a small delay on 2H71 (17:20 HWY-MYB) too. It's a capacity issue which is very difficult to solve unless you throw an awful lot of money at it eg; rebuild the down side of Gerrards Cross station with a south facing bay, install the bay platform at Denham and withdraw the Gerrards Cross terminating service to Denham (which would be very unpopular) or reinstate through lines at Beaconsfield and extend the Gerrards terminating service to Beaconsfield which would require a timetable recast. I'm not sure it would do too much damage to diagramming considering how long trains can spend in that turnback at Gerrards Cross.

As The Planner says, the Chiltern peak timetable is incredibly tight all the way through. It's a regular pastime working through the cascade of minor delays on Realtimetrains to find out why you are crawling through somewhere like Denham... quite often a delay before 1700 is still having knock on effects an hour or two later. (The same mechanism also explained why my morning train to work is so often delayed, which turns out to be regularly down to a train a couple of hours before going to somewhere completely different)

In fact it's a minor miracle that the timetable works as well as it does.

 

[The Planner]

It helps that it's pretty much Chilterns own trainset south of Aynho.

 

[berneyarms]

Very much so, but nonetheless it is a very impressive peak operation on what is a two track railway for most of the route.