Theory of General Minories

[KeithMacdonald]

58 minutes ago, Chris116 said:

How do arriving trains get to the top two platforms? 

 

Good feedback, thanks!

 

Is this better? Does it break the rules if I use double slips?

 

 

[Chris116]

1 hour ago, KeithMacdonald said:

 

Good feedback, thanks!

 

Is this better? Does it break the rules if I use double slips?

 

 

I don't worry about rules with Minories plans, just that they work and the new plan looks good from an operation point of view. Only the top platform is now departure only which could be a parcels platform so a bit of shunting will be entertaining. 

Edited November 13, 2020 by Chris116
Added a bit more

[Keith Addenbrooke]

1 hour ago, KeithMacdonald said:

 

Good feedback, thanks!

 

Is this better? Does it break the rules if I use double slips?

 

 

I’d be more concerned about the point that appears to go over the footbridge...

[KeithMacdonald]

6 minutes ago, Keith Addenbrooke said:

I’d be more concerned about the point that appears to go over the footbridge...

 

Ooo-Err!

(cough, mutter, quickly rummaging through the RMWeb Book Of Excuses)

... ah yes, here we are ... 

I've been told it was a unique one-off prototype of a very special "subway-bridge", that went under one track and up & over the next track.  Allegedly built by the same people that built the Anderton Boat Lift. But it didn't work very well and eventually got replaced by ordinary footbridges. And then the lines into platforms two and three were straightened as well, to provide a bit more platform space.

 

[Keith Addenbrooke]

On 13/11/2020 at 14:39, KeithMacdonald said:

 

Ooo-Err!

(cough, mutter, quickly rummaging through the RMWeb Book Of Excuses)

... ah yes, here we are ... 

I've been told it was a unique one-off prototype of a very special "subway-bridge", that went under one track and up & over the next track.  Allegedly built by the same people that built the Anderton Boat Lift. But it didn't work very well and eventually got replaced by ordinary footbridges. And then the lines into platforms two and three were straightened as well, to provide a bit more platform space.

 

Looking at the plan, would it be right to say that two single slips would work just as well: 

 

You need to be able “turn left” out of platform 2 for departures, and “turn left” into Platforms 3 to 5 for arrivals, but a pair of “outward facing” single slips would achieve that.  The ‘left side’ of the diamond (as drawn) is then for departures, and the ‘right side’ for arrivals, so simultaneous movements can take place:

 

(Sorry, pictures no longer available)

 

 

 It’s true all movements in and out of P4 / P5 must still go through “L”  but that is unavoidable at Minories.  Is this right?

Edited October 7, 2022 by Keith Addenbrooke
Edited for text only as photo no longer available

[KeithMacdonald]

1 hour ago, Keith Addenbrooke said:

Looking at the plan, would it be right to say that two single slips would work just as well: 

 

You need to be able “turn left” out of platform 2 for departures, and “turn left” into Platforms 3 to 5 for arrivals, but a pair of “outward facing” single slips would achieve that.  The ‘left side’ of the diamond (as drawn) is then for departures, and the ‘right side’ for arrivals, so simultaneous movements can take place:

 

 

 It’s true all movements in and out of P4 / P5 must still go through “L”  but that is unavoidable at Minories.  Is this right?

 

@Keith Addenbrooke More good feedback, thanks.

That looks one "L" of a weakness in the design.

At the very least, it would be a bottleneck in operations.

 

What happens (I wonder) if the ladder of double (or single) slips is extended to form a ladder? Is it too extreme (or bonkers) for a Minories layout? Or would it incur the wrath of the purists / Rivet Counters?

 

[Pacific231G]

1 hour ago, Keith Addenbrooke said:

Looking at the plan, would it be right to say that two single slips would work just as well: 

 

You need to be able “turn left” out of platform 2 for departures, and “turn left” into Platforms 3 to 5 for arrivals, but a pair of “outward facing” single slips would achieve that.  The ‘left side’ of the diamond (as drawn) is then for departures, and the ‘right side’ for arrivals, so simultaneous movements can take place:

 

 

 It’s true all movements in and out of P4 / P5 must still go through “L”  but that is unavoidable at Minories.  Is this right?

I think that's right and apart from p4-P5 you've also got simultaneous arrivals and departures with  any two platforms (provided obviously that the departure is from a lower platform no. than the arrival is going to) which would enable a very intensive service. Very neat. You could achieve that for P4& 5 by  replacing the facing point coming out of P3 with a single slip and adding a  departure point for P3 

 

Far from incurring the wrath of purists and certainly not bonkers, extending the double ladder of arrival and departure tracks as Keith suggests is exactly what the the Chemin de Fer de l'Est's Traffic Department came up with as a theoretically ideal commuter terminus. They did a lot of fairly deep thinking about the problem when they needed to get a more intensive rush hour service in, and especially out of, their Paris-Bastille terminus in the 1920s (Think Fenchurch Street on steroids!) without spending any real money on new infrastructure, or electrification

In the ideal case the arrival and departure "feeder" lines are separate and single directional which would have simplified signalling.  In real termini space and shape got in the way of this ideal arrangement but I think you can see the same basic  pattern in this schematic of Bastille and its signalling before and after it was rationalised . With very little length between the platform ends and a narrrow viaduct they had to compress it somewhat and that also required the use of unusualy short points so they had to avoid any S curves. (The schematic is straight but the actual approach was angled)   It does still though obey the rule of parallel moves that the earlier trackplan didn't.

 

 

 

Their traffic engineer wrote learned papers about all this (I have one of them and it consists of  13 fascinating pages of fairly dense text, diagrams and equations) but in practical terms they did manage to increase the rush hour capacity of the terminus by about 20-25% and that was with loco hauled trains turning over not push-pull working.

Hmmm. Short points and the need to avoid buffer locking by not having reverse curves, it does sound familiar doesn't it.

 

Edited November 13, 2020 by Pacific231G

[Keith Addenbrooke]

On 13/11/2020 at 17:11, Pacific231G said:

I think that's right and apart from p4-P5 you've also got simultaneous arrivals and departures with  any two platforms (provided obviously that the departure is from a lower platform no. than the arrival is going to) which would enable a very intensive service. Very neat. You could achieve that for P4& 5 by  replacing the facing point coming out of P3 with a single slip and adding a  departure point for P3 

 

Far from incurring the wrath of purists and certainly not bonkers, extending the double ladder of arrival and departure tracks as Keith suggests is exactly what the the Chemin de Fer de l'Est's Traffic Department came up with as a theoretically ideal commuter terminus. They did a lot of fairly deep thinking about the problem when they needed to get a more intensive rush hour service in, and especially out of, their Paris-Bastille terminus in the 1920s (Think Fenchurch Street on steroids!) without spending any real money on new infrastructure, or electrification

In the ideal case the arrival and departure "feeder" lines are separate and single directional which would have simplified signalling.  In real termini space and shape got in the way of this ideal arrangement but I think you can see the same basic  pattern in this schematic of Bastille and its signalling before and after it was rationalised . With very little length between the platform ends and a narrrow viaduct they had to compress it somewhat and that also required the use of unusualy short points so they had to avoid any S curves. (The schematic is straight but the actual approach was angled)   It does still though obey the rule of parallel moves that the earlier trackplan didn't.

 

 

 

Their traffic engineer wrote learned papers about all this (I have one of them and it consists of  13 fascinating pages of fairly dense text, diagrams and equations) but in practical terms they did manage to increase the rush hour capacity of the terminus by about 20-25% and that was with loco hauled trains turning over not push-pull working.

Hmmm. Short points and the need to avoid buffer locking by not having reverse curves, it does sound familiar doesn't it.

 

I must admit I do like the references to Bastille - the way it was operated by platform rotation and “re-using” incoming locomotives on outgoing trains (from your previous posts) is the other key to making it work - pure genius and avoiding conflicting train manoeuvres.

On a lighter note (it is Friday) if I call this “Gare Rue L’Un” - that might upset the purists (on several levels)?
 

(Sorry, photos no longer available)

 

Edited October 7, 2022 by Keith Addenbrooke
Edited for text only as photo no longer available

[KeithMacdonald]

4 hours ago, Pacific231G said:

Far from incurring the wrath of purists and certainly not bonkers, extending the double ladder of arrival and departure tracks as Keith suggests is exactly what the the Chemin de Fer de l'Est's Traffic Department came up with as a theoretically ideal commuter terminus. They did a lot of fairly deep thinking about the problem when they needed to get a more intensive rush hour service in, and especially out of, their Paris-Bastille terminus in the 1920s (Think Fenchurch Street on steroids!)

 

@Pacific231G I'm very glad to learn that, thanks!

[KeithMacdonald]

8 hours ago, Keith Addenbrooke said:

I must admit I do like the references to Bastille - the way it was operated by platform rotation and “re-using” incoming locomotives on outgoing trains (from your previous posts) is the other key to making it work - pure genius and avoiding conflicting train manoeuvres.

On a lighter note (it is Friday) if I call this “Gare Rue L’Un” - that might upset the purists (on several levels)?

 

Your wish is my command.

 

 

For the last few hours, I've been mulling over how one might build the “Gare Rue L’Un” from fairly normal Code 100 track without a lot of hacks or custom-made points. The outer key to it all seems to be the geometry of the double-track ladder. And the inner key to that seems to be the "rungs" of the ladder, made up of an single slipswitch (as the top half) and a right-hand point (as the bottom half).

 

Challenge #1 : What should we use for the rung of the ladder?

 

This arises because what seems like the best (or only?) Code 100 single slipswitch is the Peco SL-80, with a length of 25.1 cm.

What are the nearest (in length) right-hand points? The SL-88 is 25.9 cm, and the SL-95 is 21.95 cm.

 

The SL-88 (25.9 cm) is closest, but oh dear, there's still a 0.8cm difference. or 0.4 cm either side of a centre line. No problem if we've got something like 0.4 cm very small straight pieces to go either side. But we don't, so how do we get round that? The best I have found (so far) is to mix and match some small Hornby and Peco pieces.

 

 

A Peco ST202 is 7.9 cm, and a Hornby R610 is 3.8 cm, times two is 7.6 cm. That is 3mm. Less then the ideal 4mm, which leaves a gap of only 1 mm.

 

With me so far?

 

When we "step and repeat" that down the ladder, it's alright at first, but that pesky 1mm difference gradually accumulates.

 

Note: the first rung (or the top of the ladder) is the one on the right, and everything is fine there, but can you see what happens as we add more rungs going leftwards, going down the ladder?

 

 

(to be continued)

 

 

 

Edited November 14, 2020 by KeithMacdonald
typo

[Keith Addenbrooke]

Hi Keith.  One of the things to clarify would be what track centres you want: whether the standard Streamline 2” or the wider Setrack 2.5” (nominal).  The points used in the crossover at the end of P2 /P3 look to me like Hornby Express points, designed to maintain the standard Setrack spacing with a gentler radius?
 

On 14/11/2020 at 02:04, KeithMacdonald said:

 

Your wish is my command.

 

 

For the last few hours, I've been mulling over how one might build the “Gare Rue L’Un” from fairly normal Code 100 track without a lot of hacks or custom-made points. The outer key to it all seems to be the geometry of the double-track ladder. And the inner key to that seems to be the "rungs" of the ladder, made up of an single slipswitch (as the top half) and a right-hand point (as the bottom half).

 

Challenge #1 : What should we use for the rung of the ladder?

 

This arises because what seems like the best (or only?) Code 100 single slipswitch is the Peco SL-80, with a length of 25.1 cm.

What are the nearest (in length) right-hand points? The SL-88 is 25.9 cm, and the SL-95 is 21.95 cm.

 

The SL-88 (25.9 cm) is closest, but oh dear, there's still a 0.8cm difference. or 0.4 cm either side of a centre line. No problem if we've got something like 0.4 cm very small straight pieces to go either side. But we don't, so how do we get round that? The best I have found (so far) is to mix and match some small Hornby and Peco pieces.

 

 

A Peco ST202 is 7.9 cm, and a Hornby R610 is 3.8 cm, times two is 7.6 cm. That is 3mm. Less then the ideal 4mm, which leaves a gap of only 1 mm.

 

With me so far?

 

When we "step and repeat" that down the ladder, it's alright at first, but that pesky 1mm difference gradually accumulates.

 

Note: the first rung (or the top of the ladder) is the one on the right, and everything is fine there, but can you see what happens as we add more rungs going leftwards, going down the ladder?

 

 

(to be continued)

 

 

 

 

Back in June I did a similar exercise with the geometry - in my case to add a 3rd line for ECS movements (this is from page 42 - from memory I was working to 2” track centres):

 

On 12/06/2020 at 14:04, Keith Addenbrooke said:

I really like Chris116’s Twig Street Branch addition to Minories, and Harlequin’s Seironim is quite remarkable in just 7’.   I’m convinced by the elegance of Zomboid’s hidden junction, so have no desire to try and add to any of these: I think they complement Minories really well.

 

I did want to have another look at a junction throat for Minories, as Compound2632 spotted my "Fig 3: Double Junction" yesterday doesn’t allow full Minories operation.  Growing up near Birmingham I was quite used to Moor St (before the Snow Hill Tunnel was reinstated), so three approach tracks to a three platform station was normal to me – IIRC, the 3rd line was bidirectional for ECS movements out to Tyseley coach yard (and used single slips to reach all platforms?).  I think Model Trains magazine did a feature on Moor St in the early 1980s, but my copy is long gone now.  Can I replicate that kind of operation here though?

 

(Note: I’ve given myself an extra 6” for the pointwork – 4’ rather than 3’6”).

 

Fig A: “Adding an ECS line”

 

(Sorry, pictures no longer available)

 

I don’t really like having the double slip so central – every train movement other than Platform 1 Down departures must pass through it (8 out of 9 routes).  In Nearholmer’s sketch yesterday there was a single slip for the third running line (the Twig branch) but it only served Platform 3.

I can't see this getting approved.

 

Fig B: “ECS line to the North”

 

(Sorry, pictures no longer available)

 

I’m not sure this is an improvement – every ECS movement must go through E and cross / block both UP and Down Lines (a Double Slip would introduce a reverse curve, but this alternative sends Platform 1 ECS movements through E as well).  My guess: not approved.

 

Fig C: “Double spine”

 

(Sorry, pictures no longer available)

 

Although this is starting to lose the simplicity of Minories, a second spine reduces the pressure on E: Platform 1 Down departures and Platform 1 ECS movements go through F, and with the remaining ECS movements using the central spine only 5 of 9 routes now pass through E.

 

Fig D: “Double Parallelogram”

 

(Sorry, pictures no longer available)

 

Adding a second single slip adds redundancy as it means departures from Platforms 2 or 3 can use the central spine as an alternative to E (as can light engine movements from the Loco Siding to Platforms 2 and 3). 

 

If the central spine is used for Platform 2 and 3 departures, then only incoming trains need to pass through E, which is on the Up line anyway and is only preceded by a trailing point.

 

Platform 1 Down trains go through the second single slip point in a trailing direction.

 

Triple simultaneous operation is now possible: Platform 1 ECS or light engine / Platform 2 Down / Platform 3 Up.

 

Although I think this works geometrically and route-by-route, I don’t know enough to know if this would be how the prototype would approach the problem?  The point has been made about signalling, which I'm afraid I don't know enough about to comment on, sorry.

 

A final comment re: Moor St.  In the late 70s / 80s there was a fourth line adjacent to Platform 3 for storage.  Here we have the kickback siding instead.  As all trains were DMU’s by then, there were no loco movements (and I think the traversers had been removed).

 

 

To make it work I used the Peco Streamline Short points alongside the Single slips, then closed the gaps with short pieces of straight track.  In Anyrail I used Flextrack cut to length, but if I were building it I would actually cut pieces of straight Setrack to fit - it maintains the rigidity so ensures the filler pieces are kept straight.  Keith.

Edited October 7, 2022 by Keith Addenbrooke
Edited for text only as photo no longer available

[Joseph_Pestell]

It seems to me that, if you want a six-platform Minories, the best way is to put two three-platform Minories side by side and have a four-track approach, something like Charing Cross.

[St Enodoc]

1 hour ago, Joseph_Pestell said:

It seems to me that, if you want a six-platform Minories, the best way is to put two three-platform Minories side by side and have a four-track approach, something like Charing Cross.

...which isn't all that different from what @Clive Mortimore has done with Sheffield Exchange.

[Joseph_Pestell]

29 minutes ago, St Enodoc said:

...which isn't all that different from what @Clive Mortimore has done with Sheffield Exchange.

Indeed. Or another real life example at Bradford Exchange.

[Chimer]

 

9 hours ago, KeithMacdonald said:

A Peco ST202 is 7.9 cm, and a Hornby R610 is 3.8 cm, times two is 7.6 cm. That is 3mm. Less then the ideal 4mm, which leaves a gap of only 1 mm.

 

With me so far?

 

When we "step and repeat" that down the ladder, it's alright at first, but that pesky 1mm difference gradually accumulates.

 

I don't think you need to worry about the "pesky 1mm gap" accumulating.  That's basically the gap you get anyway when you fit bits of track together, allows for a bit of expansion, and is roughly the space taken up by the separator piece of an IRJ.  I don't think most of us lay track quite as precisely as the CAD packages assume we do ....

[Clive Mortimore]

32 minutes ago, St Enodoc said:

...which isn't all that different from what @Clive Mortimore has done with Sheffield Exchange.

 

2 minutes ago, Joseph_Pestell said:

Indeed. Or another real life example at Bradford Exchange.

Hi Sainty and Joseph

 

The idea actually comes from the 1977 remodelling of Kings Cross reducing it down to 8 platforms and adding a center road to one. Bradford Exchange was a huge influence of two railways sharing the same station (even the same two railways).

 

The red is what was added and the blue what was removed.

 

1 hour ago, Joseph_Pestell said:

It seems to me that, if you want a six-platform Minories, the best way is to put two three-platform Minories side by side and have a four-track approach, something like Charing Cross.

The suburban side of Charing Cross makes for a good Minories type layout. Andi Dagworth was looking at it as a possible layout, I did try and help by doing some track plan drawings, sadly I cannot find where I filed them.

[whart57]

Platforms 15-18 at London Victoria might work as well. In earlier times there was also a turntable and some loco stabling sidings on the way up to the bridge over the Thames

[KeithMacdonald]

6 hours ago, Keith Addenbrooke said:

Hi Keith.  One of the things to clarify would be what track centres you want: whether the standard Streamline 2” or the wider Setrack 2.5” (nominal).  The points used in the crossover at the end of P2 /P3 look to me like Hornby Express points, designed to maintain the standard Setrack spacing with a gentler radius?
 

To make it work I used the Peco Streamline Short points alongside the Single slips, then closed the gaps with short pieces of straight track.  In Anyrail I used Flextrack cut to length, but if I were building it I would actually cut pieces of straight Setrack to fit - it maintains the rigidity so ensures the filler pieces are kept straight.  Keith.

 

Well spotted - yes, it is a couple of Hornby Express points (R8078 and R8077). It took me a while to remember why. It was the knock-on effect of me getting lazy and using a Hornby R628 (curve radios 85cm) next to the single slip at the "top" of the ladder. Then I had to use the Hornby Express points to get the platform tracks parallel again.

 

 

 

[Flying Pig]

11 hours ago, KeithMacdonald said:

Your wish is my command

 

A couple of tweaks if I may, Keith.  First, trains departing over the outer road of the ladder and the double slip at the throat would block any arrivals, so I don't think anything is lost by simplifying the throat and routing departures by the inner road of the ladder.

 

Second a single slip at the end of platform three allows a much smoother departure from that platform and all the slips in the ladder can now be singles. The cost is that part of the reverse curve for trains arriving in platform 3 is over the rather tight curve of the slip.

 

 

 

 

 

[KeithMacdonald]

@Compound2632 @RJS1977 @Chimer @Keith Addenbrooke @Chris116 @Clive Mortimore @Pacific231G @Flying Pig

(and @ Chemin de Fer de l'Est's Traffic Department)

 

Thanks to all for the feedback and suggestions, especially the timely reminder about the importance of the track spacing on the curves, which I'd lost sight of. In response, here's "version 3" of the basic ladder for the “Gare Rue L’Un”, with a simpler and cleaner layout. 

 

 

The components are :

• Peco SL-80 single slips for access to each platform track
• One Peco SL-90 double slip at the station throat (for flexibility of operations)
• Peco SL-88 right-hand points
• Peco ST-202 79mm straights
• Peco Flextrack cut into 70mm straights
• Hornby 38mm R610 straight (used as a spacer between the single slips and the curve of the SL-88 points)

Some might ask:

Why am I putting in a R610 straight as a spacer?

(a) to give a 60mm track centre on the curves (just as a precaution for the overhang with long coaches going through the curves)

(b) because I'd much rather trim the sleepers off of a little discardable £1 item than a much more expensive slip (£40?)

 

Some extra short straights will get added later (to give space for the platforms between tracks coming off the slips)

 

[Pacific231G]

13 hours ago, KeithMacdonald said:

 

 

 

When we "step and repeat" that down the ladder, it's alright at first, but that pesky 1mm difference gradually accumulates.

 

Note: the first rung (or the top of the ladder) is the one on the right, and everything is fine there, but can you see what happens as we add more rungs going leftwards, going down the ladder?

 

 

(to be continued)

 

 

 

I wouldn't worry about the cumulative gap Keith. In reality you may well need some insulating rail joiners and they add a millimtere to the gap in any case. 

The ladder avoids immediate S curves except for trains leaving platform two or entering platform three. That will give you a lot of excess throwover bertween carriages and Peco's slips are effectively two foot radius.

That's always been the remainng weakness with Minories, even with three foot radius points (the genius of CJF's plan was to reduce the number of unseparated reverse curves on the six routes from 4/6 to 1/6)  This is a rule one situation of course where, unless you're actually using authentic couplers, it's up to you how much throwover you find acceptable and will also be affected by the sort of stock you're using. 

Edited November 14, 2020 by Pacific231G

[KeithMacdonald]

@Flying Pig Looks like your tweak crossed in the post

 

I like it, here it is applied (with thanks) - that gets rid of the double-slip.

 

 

 

 

[KeithMacdonald]

I keep looking at that unused white space near the tunnel entrance. Should it be filled with something? If so, what would be good?

[Flying Pig]

31 minutes ago, KeithMacdonald said:

I keep looking at that unused white space near the tunnel entrance. Should it be filled with something? If so, what would be good?

 

You are approaching the "you missed a bit" school of design

 

[Budgie]

3 hours ago, KeithMacdonald said:

I keep looking at that unused white space near the tunnel entrance. Should it be filled with something? If so, what would be good?

 

Staff allotments?