My recollection is that this was caused by a long-standing failure (of what, I do not remember, sorry!) which was low down the priority list to be fixed. What this might therefore mean is that this has finally been rectified. I agree with you that up trains have been required to come to a stand at CE 154 for a number of years now, not just a number of months.
It would be very nice if this is the case and, whatever the fault was, has been fixed! They have been doing a lot of signal head replacements around Crewe over Christmas so maybe it was resolved at the same time?
I believe the Temporary Approach Control Link was out for the main routes, effectively enforcing Warner aspect conditions onto the Main routes. This was apparently in response to concerns over substandard restricted overlap lengths at the next signals, in particular the one at the diamond crossing.
Has Crewe now got some LED signals within the station area then?
I seem to remember being told a very long time ago that the problem was that there's a faster diverging route ahead of 107 than the one into platform 6, which is 50 — the first of the two crossovers south of the station from the down fast to the up fast (signalled by Position 4 lights on 107) is for 60 (though the second, signalled by "U", is only for 20). So if there were flashing yellows, it would have to be that 60 route they would apply to. (But a question to anyone who knows: if the speed gap between two diverging routes is only 10 mph, can't you use flashing yellows for both?)
A book that I have has a section on Approach control with flashing yellow aspects while it does not mention limits it does start off with saying that 'the diverging route where the approach speed is relatively high and the junction has been specially laid out to allow it'.
Perhaps for the up movement from CE154 to down road CE148 originally had a reduced (rather than restricted) main overlap clear of the diamond that had no approach release because all moves from the signal are slow enough according to the signalling principes at the time of resignalling (all lines 20mph both directions hence no approach release required normally). Subsequent junction risk analysis, (possibly prompted by an incident?) may have identified an unacceptable collision risk for that particular route, for which quick mitigation could have been to apply TACL, a technicians terminal restriction available instantly for any signal, but the collateral is that has to apply to all routes from the signal concerned, including the straighter routes to the upside island with much lower junction collision risk. If engineers have been engaged in modifying interlocking data for (say) revised main filament alarms i.c.w. changing to LED signal heads, then the opportunity may also have been taken to 'tackle' (sorry!) a list of other minor issues in the particular interlocking area, of which 'properly' changing the approach release conditions for certain routes from CE 154 (allowing the TACL control to be removed) may be one. My experience is that most installations have lists of these kinds of issues that are rolled up periodically into a data change.
Thank you, good that it's been fixed.
As far as I can tell the restrictions have been lifted for all movements - certainly you can be signalled straight across the WCML and into 6 now and you'd expect that to be the most restrictive move?
It wasn't an actual stand - at least not in recent years anyway. Most of the time it would clear when the train was at about a walking pace and about to stop safely short of the signal.
The most likely change is that the route from CE154 to CE148 has had approach control from red added as part of a conversion to 'warner' class, which will automatically upgrade to 'main' class when a route is set forward from CE148, resulting in immediate clearance of CE154 wherever the train is on approach. Hence the delayed yellow aspect at CE154 only applies when CE148 is at red. I saw both signals off for a 1Vxx train routed to platform #6 on the open train times map earlier. Now the TACL restriction has been removed, the other routes from CE154 can clear immediately whenever their entire route and overlap extents are clear.
The Warners existed, along with step-up to Main, so far as I know, but was being overridden at the last point in aspect level by the TACL being out. Prior to this change 154 would sit at red until the berth was occupied (and it's a very short berth, which resulted in trains being almost at a stand) even with the following signal off.
Measured on Google Earth, it looks like there's just over 55m from CE148 to the clearance point for the first conflict at the diamond, which at approach speed of 20mph would be enough theoretically to justify a REDUCED overlap of exactly that figure (rather than RESTRICTED) under principles in force at the time of last resignalling, so possibly no need even for a warner route from CE154 for this particular route on the face of it. (Ref. old Railway Group Standard GK/RT0064 (and earlier similar SSPs) - Provision of Overlaps, Flank Protection and Trapping). It's very tight though (only just over 55m), and a very busy traffic location, so probably scores fairly high on overrun risk assessment, especially considering the next conflict is a merge onto the neighbouring up fast line, then wreckage could end up on down fast... Thus further mitigation is probably well justified and putting an approach control on at CE154 for this route alone, whatever class it's termed, unless CE148 ahead is clear, makes much sense to reduce risk - more yellows & aws warnings further back on approach are the result. I can appreciate ability to hold a short Shrewsbury train close to the junction at CE148 while awaiting a path across the fasts is a useful feature to retain, and all without blocking a following up train from Manchester gaining access to #1 or #5.
I think using the TACL control was one of those awful 'sledgehammer to crack a nut' solutions; very effective, but needlessly affecting all routes from the signal. Probably the only option available at the time the risk was identified as unacceptable though, when there was no budget allocated or resources available to do a proper job. It was no doubt a case of accept this highly non-optimal temporary fix or sign the route out of use completely otherwise! And we all know how long temporary solutions can persist on the railway!
To my understanding, and I'm more than happy to be corrected especially if I am imprecise, a "warner route" set from a signal (such as CE 154) to the next signal (such as CE 148, which would be the route from the up Manchester line to Crewe platform 6) is a route set when a
Everyone wanted it sorted, not seen any documentation to say its been fixed as you could potentially alter the running time at some point.
With this particular issue, there has been too much emphasis in the past on raising the non-stop linespeed through Crewe. Virtually everything stops there - in pre-Covid times there was just the one Euston - Glasgow fast per hour which ran non-stop Euston - Warrington, and even that has ceased running now. Would a speed reduction to (say) 60 mph on the Down Fast enable free approach to the platforms in question? Would the capacity benefits of this outweigh the time loss (how much?) for non-stop services?
Are there no fast freights that can go through at 75? Surely it's a question of getting the layout and signalling right rather than solving a problem that didn't seem to matter to anyyone when the layout was done by slapping on a PSR.
No one is going to do anything when you have Crewe resignalling and remodelling on the horizon.
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.
Considering you will have HS2 arriving at Basford Hall, the fast line speed is likely to be high up the list.
Yes indeed, but that hasn't prevented them from cocking it up before now ...
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.
I can recall going to a meeting as a Councillor where we were told resignalling would be necessary in the next five years.
