Four track for Filton Bank - ongoing discussion

[whole diary]

[IndustryInsider]

Thats a new one on me II, and I really don't understand why as the signal spacing distances are different and conversion from 3-Aspect to 4-Aspect signalling would most likely involve repositioning the signals anyway.  Also a bit misleading for drivers, who have been briefed differently.....  I think your latter theory might be the correct one

Yes, it seemed to start several years ago on the section between Reading and Didcot, which is 3-aspect, but could really do with being 4-aspect.  I assumed 4-aspect was imminent, but as you say, signal spacing would need to be changed (or additional signals inserted), otherwise it would take an age to get from red to green after a train has passed.

More recently, the signals between Wolvercote and Tackley installed as part of this summers resignalling are 4-aspect signal heads which only display three aspects.  At the Wolvercote end I believe Phase 2 of the Oxford Corridor Enhancement scheme will result in them becoming full 4-aspect signals, but not at the Tackley end.

[metalrail]

Dave, I wrote about the reversible working at Filton Abbey Wood in a post above: http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg251122#msg251122  and if you look at the track layout I posted here, all is explained: http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg236581#msg236581 and http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg248151#msg248151

This bidirectional section when it's commissioned will at least alleviate the bottleneck I was worried about between BPW^» (Bristol Parkway - next trains) and the relief lines south of FIT.  I always wondered why Filton Junction wasn't going to be re-modelled to allow southbound 'local' services to access P3 at FIT to prevent them holding up southbound XC^▸ (Cross Country Trains (franchise)) and the new IET^▸ (Intercity Express Train)'s on the down main

At least this way we'll have parallel running so that trains using the down main can go straight from BPW thru P1 at FIT, allowing stopping services from BPW to call at P2 at the same time.  And will also avoid a conflict with local stopping services coming from Cardiff using P3

Very well thought out   

[SandTEngineer]

OK then.  PRELIMINARY ROUTE INDICATOR (PRI).  These are used to give information to train drivers as to the route that is set ahead at a diverging junction where the aspect at the junction signal itself is already cleared for the route ahead (what is known as an UN-RESTRICTED ASPECT).  It consists of a MAIN ROUTE INDICATOR box that displays an arrow that repeats that of the junction signal itself, with the addition of a vertical arrow that shows if the junction signal route is set for the high speed route without any form of junction indication.

Here is an example showing that the route is set for the high speed divergence at the junction signal ahead (sorry but the website concerned will not allow copying of the images here so you need to follow the links):

5th image down here http://www.railsigns.uk/photos/p_route2/p_route2.html

They can be stand alone indicators (as in the case of the new one at Horfield Junction) or combined with any other type of signal as here:

Bottom image here http://www.railsigns.uk/photos/p_repsig1/p_repsig1.html

There can also be outer and an inner PRI to give more advanced warning in particular where the junction divergence is high speed in both directions.

I once designed the circuits for one of the inner and outer types at Colwich Junction on the WCML^▸ (West Coast Main Line), and its probably one of the most complex bits of interlocking design I have ever done in my soon to be 50-year long S&T^▸ (Signalling and Telegraph) career

[SandTEngineer]

Dave, I wrote about the reversible working at Filton Abbey Wood in a post above: http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg251122#msg251122  and if you look at the track layout I posted here, all is explained: http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg236581#msg236581 and http://www.firstgreatwestern.info/coffeeshop/index.php?topic=13113.msg248151#msg248151

This bidirectional section when it's commissioned will at least alleviate the bottleneck I was worried about between BPW^» (Bristol Parkway - next trains) and the relief lines south of FIT.  I always wondered why Filton Junction wasn't going to be re-modelled to allow southbound 'local' services to access P3 at FIT to prevent them holding up southbound XC^▸ (Cross Country Trains (franchise)) and the new IET^▸ (Intercity Express Train)'s on the down main

At least this way we'll have parallel running so that trains using the down main can go straight from BPW thru P1 at FIT, allowing stopping services from BPW to call at P2 at the same time.  And will also avoid a conflict with local stopping services coming from Cardiff using P3

Very well thought out   

Health Warning: It will only perform as good as the information that will be programmed into the AUTOMATIC ROUTE SETTING system, so don't expect the Filton 4T project to solve all the delay issues...

[metalrail]

Health Warning: It will only perform as good as the information that will be programmed into the AUTOMATIC ROUTE SETTING system, so don't expect the Filton 4T project to solve all the delay issues...

Yeah as I was writing it I was wondering if ARS^▸ (Automatic Route Setting) would be programmed to only ever route ALL trains from BPW^» (Bristol Parkway - next trains) to BRI^» (Bristol Temple Meads - next trains) thru FIT P1, and that the bidirectional option to use FIT P2 would only be used in dealing with delays etc...  we shall wait and see!

[Red Squirrel]

Is anyone able to explain to me the difference between ARS^▸ (Automatic Route Setting) and Electronic Live Block Overlays?

[metalrail]

They can be stand alone indicators (as in the case of the new one at Horfield Junction) or combined with any other type of signal as here:

Seeing as the actual junction signal on the Up Relief is now in place as per the pic I posted the other day, would it be sensible to assume this Prelim Route Indicator will be placed just south of Constable Rd bridge?

[SandTEngineer]

They can be stand alone indicators (as in the case of the new one at Horfield Junction) or combined with any other type of signal as here:

Seeing as the actual junction signal on the Up Relief is now in place as per the pic I posted the other day, would it be sensible to assume this Prelim Route Indicator will be placed just south of Constable Rd bridge?

Its actually about 300m North of MULLER ROAD bridge (wherever that might be).  Just about where the old running line formation transition from Up side to Down side used to be.

[SandTEngineer]

Is anyone able to explain to me the difference between ARS^▸ (Automatic Route Setting) and Electronic Live Block Overlays?

Youv'e lost me there Red Squirrel.  Tried looking that one up with no success.

[metalrail]

They can be stand alone indicators (as in the case of the new one at Horfield Junction) or combined with any other type of signal as here:

Seeing as the actual junction signal on the Up Relief is now in place as per the pic I posted the other day, would it be sensible to assume this Prelim Route Indicator will be placed just south of Constable Rd bridge?

Its actually about 300m North of MULLER ROAD bridge (wherever that might be).  Just about where the old running line formation transition from Up side to Down side used to be.

Ah...  doubtful we'll be able to see it then apart from a passing train.  Not found any decent vantage points yet around where the track used to slew as I really wanted to photograph that part when they cut the line to make the new formation, unless anyone else has?

[grahame]

Ah...  doubtful we'll be able to see it then apart from a passing train. ....

Has anyone sent a drone with a camera up ??

[JayMac]

Ah...  doubtful we'll be able to see it then apart from a passing train. ....

Has anyone sent a drone with a camera up ??

Somewhat problematical with rules about drone flying close to buildings and transport infrastructure. You'd need to be a CAA^» (Civil Aviation Authority - about) certified drone pilot and gain permission from Network Rail.

[Red Squirrel]

Is anyone able to explain to me the difference between ARS^▸ (Automatic Route Setting) and Electronic Live Block Overlays?

Youv'e lost me there Red Squirrel.  Tried looking that one up with no success.

I'm sorry S&TE, I was setting it up in the hope that someone would knock it down for me: I don't know my ARS from my ELBO.

_{Electronic Live Block Overlays are a figment of my over-ripe imagination}

[SandTEngineer]

Oh, b****y.  Fell into that one outright

Anyway, think we have now exhausted all the signalling issues.  Just over one week to go to commissioning!

Shall we award a prize to the first person to travel over both the new Main and Relief line formations?

[Red Squirrel]

Out and about this afternoon, this time to Narroways and Ashley Hill:

First pic, from Narroways Hill Footbridge looking north, shows some new signals on the reliefs (well they looked new to me, I'm happy to stand corrected);
Second confirms metalrail's point about passive provision for a station at Ashley Hill - there is a goodly gap between the mains and reliefs, sufficient for quite a long island platform. Referring back to S&TE's most excellent diagram, it is clear that there is indeed also space for a platform on the mains here, which (to my simple mind) is odd given that they've just demolished the (arguably more useful) main line platforms at Stapleton Road. Hey ho.