Bi-directional signalling Patchway to Pilning

[whole diary]

[Adrian]

I noticed today that the the lines between Patchway and Pilning are now signalled in both directions.  Not sure whether this extends in the other direction to Bristol Parkway.

I realise that this means, in principle, a westbound train could now call at Pilning - though finding a long enough gap between eastbound services to fit one in might be challenging.  And theoretically I suppose it means a train could now turn back at Patchway.  Some off-peak Weston to Bristol Parkway trains are going to be terminating at Filton in the new timetable, so could perhaps be extended to give Patchway 2 trains an hour.  But I expect there's a good reason why not...

[grahame]

I realise that this means, in principle, a westbound train could now call at Pilning - though finding a long enough gap between eastbound services to fit one in might be challenging. 

You would need a gap of around 25 minutes in eastbound services. Realistically for resilience 30 minutes. Which with a 30 minute London - South Wales service and a 30 minute Cardiff - Bristol service doesn't fit.  Only on track is bidirectional, so you can't have an eastbound train climbing up to Patchway on the normally westbound line to pass the train making a Pilining call on its way out of Bristol.

Even if you upset the timetable occasionally, I don't think you could do it often enough to tip the service at Pilining over the "usable normal service" pivot.

[SandTEngineer]

Both lines are bi-directionally signalled through the Severn Tunnel between Severn Tunnel Junction and Severn Tunnel East.  The Up Line only is bi-directionally signalled between Severn Tunnel East and Patchway.  No facilities at Patchway to reverse trains there, but they could run to Pilning wrong line and reverse back at Severn Tunnel East.

Edit to Add:  All commissioned on 04/01/2010

[Western Pathfinder]

I noticed when I visited yesterday,that new overhead signals have been installed at the western end of the station .

[Adrian]

Both lines are bi-directionally signalled through the Severn Tunnel between Severn Tunnel Junction and Severn Tunnel East.  The Up Line only is bi-directionally signalled between Severn Tunnel East and Patchway.  No facilities at Patchway to reverse trains there, but they could run to Pilning wrong line and reverse back at Severn Tunnel East.

Edit to Add:  All commissioned on 04/01/2010

At the west end of Patchway station a signal has recently appeared on the down line in the westbound direction.  Since there is not a crossover between there and Pilning, does that not imply the down line is also bidirectional now?

[SandTEngineer]

Both lines are bi-directionally signalled through the Severn Tunnel between Severn Tunnel Junction and Severn Tunnel East.  The Up Line only is bi-directionally signalled between Severn Tunnel East and Patchway.  No facilities at Patchway to reverse trains there, but they could run to Pilning wrong line and reverse back at Severn Tunnel East.

Edit to Add:  All commissioned on 04/01/2010

At the west end of Patchway station a signal has recently appeared on the down line in the westbound direction.  Since there is not a crossover between there and Pilning, does that not imply the down line is also bidirectional now?

Did you mean the Up Line in the Down direction or Down line in the Up direction?  There has always been a signal (NT1003) on the Down line in the Down direction.

[Adrian]

Both lines are bi-directionally signalled through the Severn Tunnel between Severn Tunnel Junction and Severn Tunnel East.  The Up Line only is bi-directionally signalled between Severn Tunnel East and Patchway.  No facilities at Patchway to reverse trains there, but they could run to Pilning wrong line and reverse back at Severn Tunnel East.

Edit to Add:  All commissioned on 04/01/2010

At the west end of Patchway station a signal has recently appeared on the down line in the westbound direction.  Since there is not a crossover between there and Pilning, does that not imply the down line is also bidirectional now?

Did you mean the Up Line in the Down direction or Down line in the Up direction?  There has always been a signal (NT1003) on the Down line in the Down direction.

Down line in the up direction.  Other side of the tracks to signal no 1536 I think.

[SandTEngineer]

Thats new signal BL1538.  It will allow a Down train to reverse west of Patchway station back in the Up direction.  As far as I am aware there is no plan to make the Down Line fully reversible to/from Severn Tunnel East.  Not sure when its going to be commissioned though.  I'll try and find out from a few contacts.

[Adrian]

Thats new signal BL1538.  It will allow a Down train to reverse west of Patchway station back in the Up direction.  As far as I am aware there is no plan to make the Down Line fully reversible to/from Severn Tunnel East.  Not sure when its going to be commissioned though.  I'll try and find out from a few contacts.

Yes, that's the one - I checked its number today.  If it was just to provide a turnback facility, wouldn't they have put it at the east end of the station so that the train could stop at the platform?  I also wondered if it had any use in connection with the rebuilding of Gypsy Patch Bridge if single line working was needed for a while.

[SandTEngineer]

Thats new signal BL1538.  It will allow a Down train to reverse west of Patchway station back in the Up direction.  As far as I am aware there is no plan to make the Down Line fully reversible to/from Severn Tunnel East.  Not sure when its going to be commissioned though.  I'll try and find out from a few contacts.

Yes, that's the one - I checked its number today.  If it was just to provide a turnback facility, wouldn't they have put it at the east end of the station so that the train could stop at the platform?  I also wondered if it had any use in connection with the rebuilding of Gypsy Patch Bridge if single line working was needed for a while.

Thats because signals reading in the same direction on adjacent lines are normally located parallel to each other to avoid potential mis-reading issues.

I believe this facility is being added to provide an additional entrance/exit facility to the Hitachi IET^▸ (Intercity Express Train) depot, although its been on the Signalling Scheme Plan since 2013!

[stuving]

I believe this facility is being added to provide an additional entrance/exit facility to the Hitachi IET^▸ (Intercity Express Train) depot, although its been on the Signalling Scheme Plan since 2013!

Ah - that begins to make sense of it. While close to Bristol, that depot has no direct route to or from it. Currently it always involves a reversal in Bristol Parkway and using the eastward connection. The second connection, to the north, is only usable if you can reverse on the line somewhere around Patchway.

[SandTEngineer]

I believe this facility is being added to provide an additional entrance/exit facility to the Hitachi IET^▸ (Intercity Express Train) depot, although its been on the Signalling Scheme Plan since 2013!

Ah - that begins to make sense of it. While close to Bristol, that depot has no direct route to or from it. Currently it always involves a reversal in Bristol Parkway and using the eastward connection. The second connection, to the north, is only usable if you can reverse on the line somewhere around Patchway.

Lesson No.1 when designing any depot, is always to have more than one diverse entrance/exit.

[IndustryInsider]

Indeed, especially a large one like Stoke Gifford.

[Oxonhutch]

Or like the three exits from the new Reading depot - the country end one reversing at Tilehurst with a fixed red signal (T1779) on the down side of the Up Relief; similar to Pilning.

For many years in Blackpool - TonyK might well remember - there was a gloriously ramshackle single line that ran down the backstreets of town; an escape route should the main entrance to Rigby Road depot get blocked. Alas no more 

2009 photo