Approach control signalling at Crewe

[craigybagel]

I realise that, but it is worth flagging up in the hope that - when the time comes - people might concentrate more on capacity and flexibility and less on non-stop speed.


Hardly any. Most freights run via Basford Hall and / or the Independent Lines. A few e.g. Daventry - Scotland DRS services do run through non-stop on occasion, but they are just as likely to stop for a crew change. So you wouldn't design the layout around non-stop freight speeds in this instance.

Most of them probably switch tracks somewhere in the Crewe area too, as they will probably be using the Slows to the north or south or both. The Up Slow switches sides through the station so through trains must cross the layout, and a train running through on the Down Slow is speed restricted through the station.

Late at night when the WCML is often a 2 track railway you quite often see freights passing through the middle roads at line speed, but that's about it. Freight in the station (rather than the independents) is rare enough during the day as it is, never mind any of that going through the through roads.

 

[The Planner]

I can recall going to a meeting as a Councillor where we were told resignalling would be necessary in the next five years.

I ceased being a councillor in 2009.

Sellotape goes a long way.

 

[Class 170101]

Any time gain currently made will be kept by the performance team to improve their statistics.

 

[CW2]

Any time gain currently made will be kept by the performance team to improve their statistics.

Good. The last thing that is needed is any tightening of the schedules at a congested complicated location.

 

[Joseph_Locke]

Good. The last thing that is needed is any tightening of the schedules at a congested complicated location.

... and its looking like a better layout is the last thing you'll be getting at Crewe!

 

[MarkyT]

I don't disagree, the point I am making is that even with a Main route set, and the conflict at the diamond removed, because the full overlap extends through it, *and* with the forward route set *and* signal off, 154 Main was having Warner class approach release enforced via TACL, allegedly to 'fix' concerns about the risks of the short overlaps. This also applied to the other routes from 154 where the overrun risk was lower.

Unless there are other factors at play, and the TACL was out for another reason, how does restricting the Main class aspect in that manner fix a perceived problem with the Warner?

If the Warner arrangement is deficient, surely the answer is to disable that route, not fiddle with the Main? Doing that would have allowed only the worst Warner to be taken out of use individually, whereas TACL applies to all. I can't help thinking someone has got muddled and done the wrong thing ages ago.

I do know NR performance people wanted it sorting as it was delaying every train, but it seemed that no-one could initiate getting it fixed, possibly as the reasons for the disconnection had got lost over time.

I found a photo of the real control panel face at https://photos.signalling.org/picture?/19168/category/1943-2015_new_panel

Note the extra red-bezelled exit buttons for each up signal protecting the junction from the Manchester line. These are only provided where a separate warning class route is available from the entrance signal, in this case CE154, so the signaller can select it when desired. As all these signal destinations have main and warning routes available to them from CE154. I too can see no obvious layout reason for the TACL restriction. I recall TACL is sometimes used for temporary and emergency speed restriction warning arrangements, so perhaps such a restriction had been applied across the junction at some time in the past, then lifted, but someone forgot to restore the link or tech terminal control! (Sorry can't remember if Crewe was a late RRI or early SSI installation)

explain what the term "Warner" means?

A 'warning' class route has a short 'restricted' (not 'reduced') overlap at its destination signal, and imposes a 'delayed yellow' approach release restriction at the entrance signal when the exit signal is at red. The purpose is to control speed on approach so the restricted overlap provides effective protection for conflicts ahead. If a route is subsequently set onwards from the exit and that signal clears immediately, the warner entrance signal can clear more quickly, even instantly, if permitted by other junction. The interlocking achieves this by automatically upgrading the warning class route to the main class route to the same destination. A 'reduced' overlap can be used at a main class route exit in lieu of a 'standard' overlap where achievable approach speed is sufficiently limited for all trains such that reduced overrun distance is considered safe, according to the GK/RT0064 lookup table I included up-thread together with appropriate risk assessment.

 

[moggie]

Crewe was one of the later BR-LMR 'SR style' FWI installations broadly in line with BRSW-67 principles. The rest of the interlocking control detail had faded into unreliable memory now.

 

[MadMac]

Crewe was one of the later BR-LMR 'SR style' FWI installations broadly in line with BRSW-67 principles. The rest of the interlocking control detail had faded into unreliable memory now.

Westinghouse job. The installers who did it moved on to Cowlairs, subsequently replaced by the guys who had cleared up their mess at Crewe.....

 

[moggie]

Indeed, WB&SCo were the main signalling contractor for the design and equipment supply. BR carried out all principles testing and fault rectification prior to commissioning. Let's just say we were busy. Very busy.

 

[MarkyT]

Crewe was one of the later BR-LMR 'SR style' FWI installations broadly in line with BRSW-67 principles. The rest of the interlocking control detail had faded into unreliable memory now.

Thanks Moggie & MadMac. I'd incorrectly assumed it may have been an early SSI in my comments earlier upthread, but then it slowly dawned on me the dates didn't really compute...

A sanity check via https://www.s-r-s.org.uk/archivebpsr.php reveals the interlocking to have been commissioned in 1985, too early for SSI:

Name​	Locking​	Design​	Commissioned​	Decommissioned​	Controlling Interfaces​	Notes​
Crewe​	RI​	BRS SW67 freewired​	19/07/1985​	​	Crewe PSB (1), Crewe PSB (2)​	Crewe PSB (1) until 23/08/2015, then migrated to Crewe PSB (2). Commissioned 0400hrs, actual commissioning date shown.​

The panel, original and replacement:

Location​	Interface Type​	Design & Model​	Commissioned​	Decommissioned​	Interlockings​	Notes​
Crewe PSB (1)​	NX(PP)[+]​	Westinghouse M5​	19/07/1985​	23/08/2015​	Alsager, Crewe​	Commissioned 0400hrs, actual commissioning date shown. Decommissioned 0120hrs.​
Crewe PSB (2)​	NX(PP)[+]​	LB Foster (TEW) SM40​	23/08/2015​	​	Alsager, Crewe​	Commissioned 0823hrs​

 

[MadMac]

Indeed, WB&SCo were the main signalling contractor for the design and equipment supply. BR carried out all principles testing and fault rectification prior to commissioning. Let's just say we were busy. Very busy.

We were very busy at Cowlairs as well.....

 

[moggie]

Thanks Moggie & MadMac. I'd incorrectly assumed it may have been an early SSI in my comments earlier upthread, but then it slowly dawned on me the dates didn't really compute...

A sanity check via https://www.s-r-s.org.uk/archivebpsr.php reveals the interlocking to have been commissioned in 1985, too early for SSI:

The panel, original and replacement:

ooh didn't know the panel had been replaced subsequently.

FWIW, discounting the 'trial' SSI at Leamington and the RETB at Machynlleth the first BR LMR SSI installation was Willesden Suburban A&B commissioned on the morning of 12th December 1988. Yes, that morning.

 

[185]

Doesn't seem to be a great improvement, brought down to 10mph from far away.

 

[craigybagel]

Doesn't seem to be a great improvement, brought down to 10mph from far away.

Trains are still often checked at CE154. It's only if there's a clear path all the way into the station it really makes a difference.

 

[185]

Trains are still often checked at CE154. It's only if there's a clear path all the way into the station it really makes a difference.

I did look, but there wasn't anything else moving that could have affected it, but still, one step closer to being a thing of the past like the last one before Lime St, spent years waiting there.

 

[8stewartt]

It definitely does make a difference. Took 6B10 through last night for the first time and had greens all the way up to 154 signal which was 2Y, 1Y at 150 into the platform then that stepped up to a green and right away fast line without spring below 20. Happy days

 

[craigybagel]

I did look, but there wasn't anything else moving that could have affected it, but still, one step closer to being a thing of the past like the last one before Lime St, spent years waiting there.

It seems that if there's traffic on the WCML, trains are getting held now at CE154 rather then at the junction itself - double blocking in effect. I've not been over it enough times to say conclusively if this is happening all the time, but it's definitely happening some times.