Hertford Loop issues 14/9 (and Gordon Hill question)

Gnarly disruption this morning, originally due to an obstruction in the Moorgate tunnels which was resolved, only for an issue to emerge at Cuffley. The up line is apparently blocked.

They seem to have worked out they can turn trains at Gordon Hill at last, but the attached is what is of interest to me... Why run this train into the down platform and not either the up platform or the bay? Can it proceed in passenger service from a shunt signal?

And what exactly is causing the kerfuffle at Cuffley? If it persists during the day the evening peak will be fun indeed.

Ta!

(Image shows a screenshot of an Open Train Times signal diagram of Gordon Hill with a train being signalled south from platform 3)

I don’t know for sure, however I would suspect the speed of the turn around matters here. The train will go into platform 3 today with no crossing movement. Then will go out as per diagram. If you went into 1 then you would have slower access in / out. There is also no blocking of other trains is nothing is going further north.

I don't know if the move is allowed in passenger service over a shunt signal, but if it isn't, it could run ECS to Enfield Chase and enter passenger service there (albeit to the annoyance of any intending passengers at Gordon Hill)

Dave W said:

And what exactly is causing the kerfuffle at Cuffley

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As well as the GN Inners being disrupted there were some delays on GN Outers to/from Kings Lynn/Ely and signalling problems in the core caused disruption on Thameslink to add to the mix.

Dave W said:

They seem to have worked out they can turn trains at Gordon Hill at last, but the attached is what is of interest to me... Why run this train into the down platform and not either the up platform or the bay? Can it proceed in passenger service from a shunt signal?

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The early turnbacks at Gordon Hill today had long dwells and formed the regular train back to London. For Stevenage trains that's about an hour waiting at Gordon Hill. 2F16 0920 from Moorgate arrived first into the bay at 1019, then 2F18 0946 from Moorgate arrived into down platform at 1045. 2F25 1101 at Gordon Hill formed from 2F16 leaving the bay empty, with 2F18 left in the down platform to form 2F27 at 1131. This arrangement minimises the number of drivers driving a unit out of position when services can run through again.

I'm not sure the up platform has a fixed red main aspect for turnback which would be a requirement for a main aspect into that platform.

Stephen42 said:

I'm not sure the up platform has a fixed red main aspect for turnback which would be a requirement for a main aspect into that platform.

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It isn't a fixed red main aspect, it's a 'Limit of Shunt' board - actually a board too, proper old school. You could only enter the up platform from the south on a position light. There's an Associated Position Light on the down line at the main aspect signal protecting the station (where you can get a theatre box 'U' for the Up Bay), or if shunting there's the Ground Position Light K201.

You can depart on a Position Light (shunt signal) in passenger service, but must have the Signaller's permission (or if it's planned, be in the Weekly Operating Notices).

i believe there is operational restriction on 717 door release on platform 2 (up platform) if coming from the down direction whilst in passenger service.

Not sure why, as the train fits the platform adequately. I can't even see it being a signal sighting issue when the driver goes the the up direction cab.

That may be why they put it in the down platform and then started service from there.

choochoochoo said:

i believe there is operational restriction on 717 door release on platform 2 (up platform) if coming from the down direction whilst in passenger service.

Not sure why, as the train fits the platform adequately.

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I've certainly been in to 2 on a 717, right at the start of their introduction - and there is a "method in the madness" on the door release restriction as if the train draws right up to the LOS board, the front doors are partially on the country end platform ramp. But there's obviously a main signal at the south end which I initially thought would be preferable, notwithstanding @whoosh's comment:

whoosh said:

You can depart on a Position Light (shunt signal) in passenger service, but must have the Signaller's permission (or if it's planned, be in the Weekly Operating Notices).

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Thanks for this - knowledge to be banked

Failed Unit said:

I don’t know for sure, however I would suspect the speed of the turn around matters here. The train will go into platform 3 today with no crossing movement. Then will go out as per diagram. If you went into 1 then you would have slower access in / out. There is also no blocking of other trains is nothing is going further north.

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Not that it matters now (and v grateful for your input!) but the not blocking of p3 isn't quite right as it seemed GN wanted to run down trains as normal (the issue was on the up line), with balancing units returning via Welwyn. Not sure how that would have been arranged at Stevenage!

In the main, since the service was heavily disrupted and there wasn't a lot knocking around to delay further, the decision not to put it into the bay at Gordon Hill was of interest, given that happens in normal operations and I'd have thought sticking as closely as possible to "normal" working would be preferable. But whatever does the job, and it did! Thanks all!

Dave W said:

I've certainly been in to 2 on a 717, right at the start of their introduction - and there is a "method in the madness" on the door release restriction as if the train draws right up to the LOS board, the front doors are partially on the country end platform ramp. But there's obviously a main signal at the south end which I initially thought would be preferable, notwithstanding

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If you were in passenger service and sent into platform 2 in the down direction, would there still be a requirement to go all the way to the Limit of Shunt ? Why could you not stop when your cab reaches the north end platform ramp. Then the passenger doors would all be on the platform, and the south end signal should still be visible ?

Are both platforms (2 and the bay) permissive ? I'm pretty sure the bay is as I think I've seen 313s coupled there in the past. Not sure about platform 2 though. So you may need signaller permission to move into platform 2 in the down direction from the associated position light.

What do they do here in normal service? In the evening many services terminate at Gordon Hill. I assume reading from above they can’t go into platform 3. I know they will be returning to London ESC so things are probably different to when they are returning in service.

Normal Gordon Hill terminators go into the bay platform under main aspect single yellow with theatre box indicator, there's a red on the buffer stop. Bay platform has a signal at the london-end.

Failed Unit said:

What do they do here in normal service? In the evening many services terminate at Gordon Hill. I assume reading from above they can’t go into platform 3. I know they will be returning to London ESC so things are probably different to when they are returning in service.

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That's the crux of it. I didn't know they could!

Perhaps there was a bit of a miscommunication and the signaller expected the train to go on to Stevenage?