Cotswold Line redoubling: 2008 - 2011

[whole diary]

[Btline]

Thanks for doing that II. Very interesting!

[Worcester_Passenger]

"Interesting" is an under-statement. Incredibly good!

[IndustryInsider]

My pleasure!

[Andy W]

Yes,II, very well done indeed - Hollywood beckons!!

[stebbo]

Found the video footage fascinating, particularly the Evesham to Pershore piece. Hadn't appreciated the extra length of double track northwest from Evesham.

[anthony215]

Haven't had a chance to watch all of them yet hopefully I will later but excellent work and thanks for taking the time to upload them.

[Chris from Nailsea]

May I also offer a formal 'thank you!' on behalf of the admin / moderator team here, IndustryInsider.  Chris. 

[Btline]

Found the video footage fascinating, particularly the Evesham to Pershore piece. Hadn't appreciated the extra length of double track northwest from Evesham.

What exactly is the point of the extra track near Evesham. Obviously, the more the better so I'm not complaining, but I'm surprised they spent money on it as it meant they had to re-do all that signalling and trackwork for very little new track.

[Andy W]

Found the video footage fascinating, particularly the Evesham to Pershore piece. Hadn't appreciated the extra length of double track northwest from Evesham.

What exactly is the point of the extra track near Evesham. Obviously, the more the better so I'm not complaining, but I'm surprised they spent money on it as it meant they had to re-do all that signalling and trackwork for very little new track.

Hi II, out of interest when does the single line 'token' get released on an up service leaving the single line going on towards Evesham and when is the token given to a down service leaving Evesham ready to enter the single line?

Do trains actually pass each other on the new double line west of Evesham or do trains actually pass at Evesham station?

[IndustryInsider]

It depends how quickly the signaller and driver/TM^▸ (Train Manager, or Ticket Machine, or Temple Meads (Bristol), depending on context)'s gets to work, but if they are really on the ball you will get a train departing Evesham in the 'down' direction as the 'up' service is passing the signalbox.  If they're not quite so quick then the train is usually just arriving in the platform as the other departs.

So, to answer your question they can just pass each other beyond the station.  I reckon it saves around 30-60 seconds on what would have happened should that short section not have been doubled.  The lack of a signal beyond the signal box in the 'down' direction probably adds 30-60 seconds on what the optimal time could have been if they'd installed one.

In my opinion, the jury remains out on whether that short additional section was worth it.

[Btline]

I'm surprised it's worth it as I presume despatch isn't started until the line is clear. So one the light goes green, by the time despatch has been finished (a lengthy process on an HST^▸ (High Speed Train (Inter City class 43 125 units))), I would imagine the other train is arriving.

Of course it should make further redoubling cheaper...

[IndustryInsider]

So one the light goes green, by the time despatch has been finished (a lengthy process on an HST^▸ (High Speed Train (Inter City class 43 125 units)))

If the TM^▸ (Train Manager, or Ticket Machine, or Temple Meads (Bristol), depending on context) has closed all the doors and the train is ready to go then it's pretty quick on a HST.  Obviously it's slower if the TM hasn't checked the doors though.

[Andy W]

Hi II, thanks for the information.

Looking at the timetable, for example the 08:56 Evesham to Worcester - the London service is due to arrive at 08:56 with 8 minutes padding until it departs at 09:04.

This means that any delay with the London bound service coming off the single line will be incurred by the Worcester service - the additional double section would be of little advantage whatsoever in this case.

At best the timetabling is at best strange - also I can't understand why the points are protected by a signal in the up direction but not on the down line.

I would have thought that any token would not be issued to an up service without the points being set correctly, so that signal should be redundant, whereas in the down direction the points should be protected by a signal close to them allowing a train to at least progress from Evesham to the start of the single line prior to the line being cleared. This would then take full advantage of that extra stretch of track.

[Adrian the Rock]

There are no tokens - not even electronic ones like they use on the RETB^▸ (Radio Electronic Token Block - a modern development of electronic token block signalling in which the token takes the form of an encoded data message transmitted to a receiver on the train. The system ensures that only one train is in possession of any single radio token at one time.) lines.  The Evesham - Norton Junction section is track-circuit block (TCB^▸ (Track Circuit Block)) with an acceptance lever at Norton Jct.  Authority to enter the single line is (normally) given solely by the cleared signals.

This means that, in principle, the route can be set for a down train from Evesham as soon as the up arrival has cleared the section plus the track circuit (ZDS) that covers the junction points.  In practice, however, the boxes would first have to have an exchange of communication something along the following lines:

E:  train out of section for [up train]
NJ:  acknowledge
E:  is line clear for [down train]
NJ:  reverse acceptance lever, then acknowledge line clear.

Then Evesham can clear the down signal.

[Andy W]

There are no tokens - not even electronic ones like they use on the RETB^▸ (Radio Electronic Token Block - a modern development of electronic token block signalling in which the token takes the form of an encoded data message transmitted to a receiver on the train. The system ensures that only one train is in possession of any single radio token at one time.) lines.  The Evesham - Norton Junction section is track-circuit block (TCB^▸ (Track Circuit Block)) with an acceptance lever at Norton Jct.  Authority to enter the single line is (normally) given solely by the cleared signals.

This means that, in principle, the route can be set for a down train from Evesham as soon as the up arrival has cleared the section plus the track circuit (ZDS) that covers the junction points.  In practice, however, the boxes would first have to have an exchange of communication something along the following lines:

E:  train out of section for [up train]
NJ:  acknowledge
E:  is line clear for [down train]
NJ:  reverse acceptance lever, then acknowledge line clear.

Then Evesham can clear the down signal.

Hi Adrian, thanks for your input. Out of interest where exactly is the track circuit (ZDS) located?

The block signal on the down line is therefore the signal at Evesham. I don't understand why there isn't a second signal just prior to entering the single line on the down side. This would allow more efficient use of the final section of re-doubled line. In fact is there a need for the signal at the station at Evesham rather than have one on the entrance to the single line?

Nor do I understand why there is a signal on the up side just prior to entering the double section as this surely must be set correctly before a train enters the single line at Norton. I'm sure there's a reason - just can't fathom it out.