Theory of General Minories

[Nearholmer]

Not something you do when you want very high availability, either, because it creates a situation whereby the failure of any one of a large number of components/sub-systems will “shut the job”.

[Zomboid]

I don't know, if you have back to back crossovers you have 4 sets of S&C, so doubling your chance of a failure there, and if one does fail then your not really in a better place, depending on which one and the failure mode.

[Dr Gerbil-Fritters]

It's not Minories, but what a fantastic modelable little terminus, with a busy steam powered commuter service...

 

[Nearholmer]

52 minutes ago, Zomboid said:

 

I don't know, if you have back to back crossovers

 

Two crossovers usually permits a degraded service to be run using at least one platform in the event of any single switch failing, whereas “all into one and out again” can be completely banjaxed by a single switch failure.

 

To get into real dependability you have to create “redundant paths”, so even more than that. It’s quite rarely done, but IIRC the channel tunnel shuttle termini have redundant paths, and I know that some LU depots do, to avoid the possibility of locking-in the whole fleet at the start of traffic.

 

The place that I am constantly awed by is Brixton on the Victoria Line, where two tracks feed two terminal platforms through a scissors crossing, that is the entire layout, and it consistently delivers 36tph in each direction. Even under manual driving a similar layout at Elephant & Castle delivers 24tph in each direction, with short burst even higher. In both cases the p&c has to be built like a BSH, and maintained in immaculate condition.

 

 

Edited March 2, 2022 by Nearholmer

[Zomboid]

57 minutes ago, Dr Gerbil-Fritters said:

It's not Minories, but what a fantastic modelable little terminus, with a busy steam powered commuter service...

 

Something about the lighting, track and field of vision makes that look very model-esque.

[Dr Gerbil-Fritters]

3 minutes ago, Zomboid said:

Something about the lighting, track and field of vision makes that look very model-esque.

 

Yes, and with the view point as well, it's very Craig and Mertonford, Railway of the Month, Railway Modeller circa 1966

[Flying Pig]

On 03/01/2022 at 11:22, Pacific231G said:

The first part of the video is in the Acheres yard and slips do nowadays seem to be far more common in yard trackage (voies de service) than on running lines (voies principales) but I did notice a number of scissors crossovers on the main line. There are slips on the approaches to Paris St.Lazare that appear in one of Railtrotter's earlier videos that I'm watching now  but they may be confined to relatively low speeds.

 

Sorry to respond late to this, but have you seen any of the videos by ForwardUntoDawn of cab rides on the lines out of Paris Montparnasse?  There seem to be plenty of slips in the approaches to larger stations and not all particularly slow.  Some very scenic trips too.

[Pacific231G]

3 hours ago, Dr Gerbil-Fritters said:

It's not Minories, but what a fantastic modelable little terminus, with a busy steam powered commuter service...

 

Is that Cergy-Pontoise? 

[Dr Gerbil-Fritters]

2 hours ago, Pacific231G said:

Is that Cergy-Pontoise? 

 

No, it's Porto Trindade, Portugal.

 

Six platforms, frequent commuter trains headed by 2-8-2T and 0-4-4-0T, diesel railcars, servicing facility, turntable, stock sidings... all on the metre gauge. 

 

I've been fascinated by it since seeing evocative colour photos in one of Colin Garrett's small books that I borrowed from my local library as a small boy.

[RJS1977]

On 02/03/2022 at 14:02, Nearholmer said:

Not something you do when you want very high availability, either, because it creates a situation whereby the failure of any one of a large number of components/sub-systems will “shut the job”.

 

Agreed - I can remember returning from Bracknell to Reading (4b) on a VEP one evening, where the driver stopped short, with the rear end of the train overhanging the pointwork. Of course, being slam-door stock with no central locking, as soon as the train stopped,  passengers who were on the carriages in the platform disembarked (despite the announcement not to do so), meaning that the train was unable to be moved until disembarkation was complete and the doors had been shut, which in turn delayed the service in 4a which was awaiting departure.

[john new]

On 01/03/2022 at 22:44, john new said:

Weymouth, current format, is double track, points into single line, then splits again into three platforms.

The route over Scarbrough Bridge in York is another one done, as I understand it, because there was a weight restriction and a single line over the bridge guaranteed it got met. Ribblehead was/(is still?) too for the same reason.

 

Edited March 12, 2022 by john new
Typo spotted on re-reading the thread.

[Zomboid]

Ribblehead was singled for weight reasons, but AIUI would now be capable of taking the full load if it were doubled. The traffic doesn't presently justify that though.

[woodenhead]

16 minutes ago, Zomboid said:

Ribblehead was singled for weight reasons, but AIUI would now be capable of taking the full load if it were doubled. The traffic doesn't presently justify that though.

It was singled because of the state it was in due to water ingress, then BR proposed to close the line and the rest is history.

 

Even now the water ingress continues to plague the viaduct and Network Rail have more remedial works to complete to keep it safe.

[john new]

Has anyone replaced the first facing point on the incoming road with a double slip so as to create a junction? 

[KeithMacdonald]

On 02/03/2022 at 20:40, Dr Gerbil-Fritters said:

No, it's Porto Trindade, Portugal.

 

Six platforms, frequent commuter trains headed by 2-8-2T and 0-4-4-0T, diesel railcars, servicing facility, turntable, stock sidings... all on the metre gauge. 

 

As the contribution from @Zomboid has got flushed round the RmWeb U-bend of ISP disasters, may I contribute a new version?

 

From TrainsandTravel on Flickr

Quote

Taken on September 25, 1967

General view of the narrow-gauge Trindade station in Porto. On the left is an Allan MEy 3xx railcar and trailer and on the right is 0-4-4-0T E?? (possibly E168).

 

 

Roll on c.50 years, and it all looks a bit different

 

 

[Regularity]

4 hours ago, john new said:

Has anyone replaced the first facing point on the incoming road with a double slip so as to create a junction? 

One slip route is superfluous: a single slip does the necessary, with the slip on the outside route.

I think I have posted this somewhere earlier in the thread.

[john new]

13 minutes ago, Regularity said:

One slip route is superfluous: a single slip does the necessary, with the slip on the outside route.

I think I have posted this somewhere earlier in the thread.

Not sure I concur. The basic arrangement as per CJF's plan allows an incoming train to access the longest platform (the standard departure road). it therefore needs a r/h curve, anything coming out of that and onto the branch would then be using the straight through part of the slip. Without the other curve though nothing coming out of platform 2 could gain the branch as it also needs a right hand curve to do so.  If the existing spur of platform 3 is retained then the two branch line roads would join somewhere behind where the the signal box is drawn. In order for both an incoming and outgoing train to have those r/hand curves available it surely does need a double slip.

[Regularity]

One wonders why you asked…

 

But anyway, here is a very quick sketch, based on something I actually started on 28 years ago.

The red slip line is unnecessary, as the green route does what is required, allowing for a simultaneous arrival and departure, and not reducing the throat to a single track.

 

[t-b-g]

7 minutes ago, Regularity said:

One wonders why you asked…

 

But anyway, here is a very quick sketch, based on something I actually started on 28 years ago.

The red slip line is unnecessary, as the green route does what is required, allowing for a simultaneous arrival and departure, and not reducing the throat to a single track.

 

 

I have seen a layout done like with a double slip. It is totally redundant and adds nothing to the operation. When queried, it was established that the layout builder couldn't find a single slip to purchase at the time so used a double as that was available.

Edited June 22, 2022 by t-b-g
To remove something I realised was daft to say!

[Flying Pig]

I think @john new means something like this - introducing a new branch line rather than just rearranging the throat.  It looks a bit crowded to me and I don't think it adds much to the operation. You can imagine any number of destinations for you trains after all (see Sheffield Exchange Mk1, which also used the single slip modification).

 

).

[Harlequin]

The trouble with using a Peco Streamline slip in the throat is that it has a nominal 2ft radius and so both the line that it's in and the parallel line take quite a sharp deviation where you don't really want it. It can also cause nasty reverse curves depending on where it's placed w.r.t other pointwork and the desired routes through it.

 

You could use another manufacturer's slip with larger radius turning routes or build your own of course, but larger radii means longer formations and then you're getting away from the whole ethos of Minories.

 

Edited June 23, 2022 by Harlequin

[Regularity]

Using hand-built track, or possibly some Tillig RTP, you can produce a much more visually satisfying look with a double slip, outside single slip, a “three-way” and a trap point:

Excluding the trap, if using the definition of a turnout per the Micro Layouts web site (a single purchased item) then this is a “3-point terminus”, per Ian Futers!

 

Edited June 23, 2022 by Regularity
Tillig outside slip.

[john new]

8 hours ago, Flying Pig said:

I think @john new means something like this - introducing a new branch line rather than just rearranging the throat.  It looks a bit crowded to me and I don't think it adds much to the operation. You can imagine any number of destinations for you trains after all (see Sheffield Exchange Mk1, which also used the single slip modification).

 

).

Yes, that but with the two lines at the front joining and curving away. I have enough pointwork lurking unused  to do it, including the d/slip, but not sure, hence the pondering if anyone else had. Didn’t risk a redraw of PECO’s plan.

[Flying Pig]

53 minutes ago, john new said:

Yes, that but with the two lines at the front joining and curving away. I have enough pointwork lurking unused  to do it, including the d/slip, but not sure, hence the pondering if anyone else had. Didn’t risk a redraw of PECO’s plan.

 

Something like this then? 

 

 

 

[Nearholmer]

It’s worth thinking about these arrangements in terms of capacity (number of trains that can be handled in and out each hour) at a real terminus.

 

Serving a two track route with two platforms, which is what this is heading to, is pretty restrictive unless the operating practices are really, really slick, the sort of thing the District did in steam days, which means making all the trains and locomotives identical. For toy train purposes, where variety adds fun, rather than trouble and expense, and one wants to include things like the odd newspaper and parcel train, it implies a lower density of service, and begs questions about all that fancy pointwork.

 

Surely the slip only needs to be single, not double, BTW, unless the ‘twig’ train runs round using the resultant loop.

 

 

Edited June 23, 2022 by Nearholmer