Great Southern Railway (Fictitious) - Looking North

[Compound2632]

Just now, Skinnylinny said:

 

Would not the distant be fixed? The down distant would require the down home and down starter to be off before it could be pulled off; as this is a terminus, the red light on the down line buffer stop takes the place of the down starter and is permanently on, so, logically, the down distant cannot be cleared!

 

Having eliminated one lever I'll introduce another. I think there should be an advance starter a train's length in advance of points 3 on the up line, so that all shunting moves can be conducted within station limits. I think this would do away with the need for the three shunt signals 9, 17, 19 but I'm not sure of this and you probably want to keep them for effect anyway!

 

A technicality for points 3 and 5: the crossover would be worked by one lever, 3, with the connection to the down side sidings worked as a second crossover - i.e. the middle of your three 5s, the one adjacent to FPL 6, should be a 3. (This would have the effect of moving 6 to 4, I suppose.)

 

Thinking about FPLs, I think the only one you need is 6, for departures from the down platform, as that is the only mover you've got for a passenger train to traverse a facing point - which demonstrates just how realistic your layout is!

 

This all makes a refreshing change from those cases where someone posts a track plan of a nearly-finished fully-sceniced layout asking where to put the signals and the only truthful answer is that you can't place signals until you've ripped up the track and started again!

[Skinnylinny]

Re: the worked distant - There were definitely instances of worked distants at termini on the LB&SCR which were signalled by Saxby & Farmer (the contractor responsible for Linton Town) - the concept being that the distant was to warn the driver of approaching trains whether they had a clear run into the platform or would have to stop at the home due to (for example) shunting moves. I've decided that as the signalling is being provided by a contractor, they would (naturally) want to sell as much equipment as possible!

For the facing point locks on 3 and 14 - I had thought that it might be helpful to be able to operate the terminus on the "one engine in steam" principle with a pull-push set or railmotor, using only the up line, if the 'box had to be switched out. This would mean 3 and 14 would become facing points. The reason for the use of the up line rather than the down line is the layout of sidings further along the line, as well as the station building being on platform 1 (the up platform).

I see your reasoning for the advanced starter. My logic is again based on what I've seen done on the LB&SC, where the platform starter allows access to the section ahead, while the shunt-ahead arm only allows movement past the arm as far as is necessary for the shunting move being carried out. Plus, again, an excuse to sell more equipment to the customer!

As for the slip/crossover lever numbering, I agree - I'll make that change. Unfortunately that'll make wiring the layout potentially more complex than switching both sets of slip blades at once, but ah well!

[Compound2632]

12 minutes ago, Skinnylinny said:

Re: the worked distant 

 

Ah, well, if you are following LBSC / Saxby & Farmer practice, then I bow to your superior knowledge. (I knew I should have put in a caveat about my ignorance of Brighton signalling practice.)

 

My remaining quibble is with your one engine in steam idea. Would the economy achieved justify the outlay on the additional FPLs and changing to the frame and locking?

[Skinnylinny]

A fair point - I've assumed that Linton Town was resignalled at some point between 1890 and 1892 post Regulation of Railways Act, and as such the signalling and interlocking was almost completely redone from scratch. As such, it makes sense to me that the railway company would re-evaluate the potential operations of the station. That being said, pull-push services didn't come into existence until 1904, so you may well be right! 

[Nick C]

If you do need FPLs on 3A* and 14A, they'd probably both be worked of the same lever - both to save equipment and as there wouldn't be room for a full locking bar between them. I agree with @Compound2632 that the right-hand end of the slip would be a crossover on lever 3. 

 

*A refers to the end closest to the signalbox for crossovers, with B for the other. In this case both ends of 3 will be about the same distance, but I'm referring to the one currently labelled 3!

 

As for the worked distant into a terminal platform - Seaford, Bognor and Littlehampton all had them, according to the Pryer diagrams.

[Skinnylinny]

Thank you both for the comments! I now have rather more spare levers (which might move about the frame a bit) but hopefully this is a bit more to everyone's liking?

 

I might also swap (8 and 9) with (10 and 11) so that the lever numbers 8-19 read down the diagram at that point. Thoughts?

[Compound2632]

Just to lob in another annoying suggestion, a feature typical of a terminus on a double track line was a facing crossover, so that down arrivals could terminate at the up platform which, as you point out, is where your main building is. This would, I think, generally be the inner crossover, per Minories - but this would be a major disruption to the layout.

[Lacathedrale]

@Skinnylinny would you be at all able to share the STLs for those levers? They look spectacular.

 

I have a filament printer too and I'd love to use them if not for mechanical actuation, then at least microswitches for servos in due course.

 

 

[Skinnylinny]

2 minutes ago, Lacathedrale said:

@Skinnylinny would you be at all able to share the STLs for those levers? They look spectacular.

 

I have a filament printer too and I'd love to use them if not for mechanical actuation, then at least microswitches for servos in due course.

 

 

Absolutely I can - they need a little fettling to get the screws to fit, but they're designed around M2x5 screws for the catch handles, 3mm threaded rod holding the quadrants together, and a 5mm rod for the lever pivot point. The springs are these: https://www.amazon.co.uk/dp/B01ERC4FX4

They are a bit delicate, in that they're slightly bendy sideways, and the catch rod retainer on the lever is not the strongest (I would love to get them cast or machined in brass or aluminium instead!), but they serve my purpose for now. Oh, and I found that I needed to use "tree" type support on the levers themselves to avoid having flattened handles where the support meets them. The Right-hand frame end is a mirror of the left-hand one.

 

Centre Frame.stl Lever.stl Left Frame End.stl Catch Rod.stl Catch Handle.stl

[Lacathedrale]

Thank you very much indeed - I must admit I'm not so sure about filament supports, I tend (in Cura) to just hit 'rectangle' and dump them where required. If it's not too much trouble could you show me what you mean? Thank you again.

 

Linton Town looks like it's going to be a cracker :)

[Skinnylinny]

No worries at all - in Cura (which is what I use), under "Support" on the print quality dropdown, you can see "Tree" under "Support Structure".


"Normal" works pretty well for the quadrants and catch handles, but do let me know if you have any other questions. I have found that the levers need printing a decent distance apart to stop the support trees interfering with one another. What printer are you using?

[Nick C]

19 minutes ago, Compound2632 said:

Just to lob in another annoying suggestion, a feature typical of a terminus on a double track line was a facing crossover, so that down arrivals could terminate at the up platform which, as you point out, is where your main building is. This would, I think, generally be the inner crossover, per Minories - but this would be a major disruption to the layout.

Both Bognor and Littlehampton (to keep with the Brighton/Saxby theme) actually had the facing crossover as the outer one, and both were signalled for arrivals into any platform. They also had vast numbers of discs, often selected by the lie of the points - 28 at Littlehampton, compared with 9 after the SR resignalling!

[Lacathedrale]

1 hour ago, Skinnylinny said:

No worries at all - in Cura (which is what I use), under "Support" on the print quality dropdown, you can see "Tree" under "Support Structure".


"Normal" works pretty well for the quadrants and catch handles, but do let me know if you have any other questions. I have found that the levers need printing a decent distance apart to stop the support trees interfering with one another. What printer are you using?

 

Do I need to set any of the other values? I've never actually ticked the 'generate support' button in my life!

 

[Skinnylinny]

Um I would say so - I have had the best success printing the levers oriented like this: 

If you can open this file in Cura, it should be oriented correctly and also hovering about 5mm above the print bed (this makes taking the supports off much easier!):

https://1drv.ms/u/s!AlUt0d-9KTAIrV8YBbQV9UfCxvRL?e=lr0hFJ

It's saved in 3mf format, which is a format that tells Cura about where to position the object. You can then click the object, copy and paste it on the print bed a few times (though I'd suggest just printing one at first to check it'll all work). 

I wouldn't have thought you would need to change any of the other settings. Once you've sliced the file, click "Preview" and hopefully you should get supports that look something like this: 

If this method helps, I'm happy to drop 3mf files with the other components.

[WFPettigrew]

3 hours ago, Nick C said:

Both Bognor and Littlehampton (to keep with the Brighton/Saxby theme) actually had the facing crossover as the outer one, and both were signalled for arrivals into any platform.

 

I agree with the idea of being able to get into the main platform from the down line, and anyway you said your one-engine-in-steam set up would require this.  So a facing crossover is needed somewhere - from what Nick says, you can have that off towards the countryside (even off scene if needed).   That would obviously require FPL and a crossover lever, plus a second home signal - and you would also need an FPL on the loco release crossover between the two platforms. 

 

The only other points I would make are that the levers 16-20 ideally need reversing - so that the P1 starter is 20 rather than 16, and with the others "inside".   I like the idea of the cluster of red levers including the P2 starter in the middle of the frame - that was certainly typical of some frames (possibly including Saxby and Farmer ones) and visually it breaks things up.  

 

And depending on the distance from the box to the loco release crossover, it might not have been possible to control that direct from the box due to the limit on rodding runs.  In addition it might not be possible to see from the box when it was the right time to change the points.   A solution here would be a lever in the box to release a ground frame operated by the loco crew but again I don't know if that was S&F/Brighton practice. 

 

All the best

 

Neil 

[Compound2632]

4 minutes ago, WFPettigrew said:

and you would also need an FPL on the loco release crossover between the two platforms. 

 

Not convinced. Points 12 are not traversed by a passenger train, since they are pretty well beyond the platform. To run round efficiently, and arriving engine would have to stop short of them.

 

Worked, I should think, by a ground frame, released from the box - certainly within 180 yards, even if the platforms are 300 ft long rather than 200 ft.

[Lacathedrale]

3 hours ago, Skinnylinny said:

Um I would say so - I have had the best success printing the levers oriented like this: 

If you can open this file in Cura, it should be oriented correctly and also hovering about 5mm above the print bed (this makes taking the supports off much easier!):

https://1drv.ms/u/s!AlUt0d-9KTAIrV8YBbQV9UfCxvRL?e=lr0hFJ

It's saved in 3mf format, which is a format that tells Cura about where to position the object. You can then click the object, copy and paste it on the print bed a few times (though I'd suggest just printing one at first to check it'll all work). 

I wouldn't have thought you would need to change any of the other settings. Once you've sliced the file, click "Preview" and hopefully you should get supports that look something like this: 

If this method helps, I'm happy to drop 3mf files with the other components.

 

My supports came out quite differently using the 3MF file, but overall it worked out. If you would be so kind as to share the other 3MFs just so I could get a working example together, then I'm happy to fiddle myself, too. What an extraordinary bit of work it is, you should be very proud!

[Skinnylinny]

Thank you! I'll have to dig out the 3mf files in the morning I'm afraid, but those look good! For the Centre Frame and Left Frame End parts I just printed them plonked flat on the print bed, laid flat so that they're not tall (if that makes sense). "Normal" supports peel off fairly readily.

[Lacathedrale]

Cheers, I think I may have it cracked apart from the catch-handles - the centre pieces are printing vertically as we speak - lovely!  I think I have two small questions for ordering the bits to go with it: is it all three through holes in the frames which use the M3 threaded rod, and are you using M2x5 self-tapping, bolts or grub screws for the catch-handle pivots?

 

Incidentally, your idea for mechanical interlocking with microswitches happens to be exactly the kind of thing I'd love to do on my layout so I'm keeping a very close eye on this!

Edited February 12 by Lacathedrale

[Skinnylinny]

Aha - I'll pop a file for the catch handles on OneDrive for you.

For the frames, yes, all three through holes take the M3 threaded rod. The catch handle pivots use plain M2x5 bolts. The holes on the catch handles print slightly undersize, so I open one out a bit with a pin vice (being very gentle with the pressure!) and let the bolt self-tap into the far side. 

 

https://1drv.ms/u/s!AlUt0d-9KTAIrWdYzsbzjtL8g5Ng?e=5gXqO8 <- single catch handle file.

[cornamuse]

That looks incredible. 

[Skinnylinny]

Thank you! I'm rather proud... But it'll be the interlocking that's the scary bit.

[Lacathedrale]

Looks fantastic! How are you expecting to drive micro switches/interlocking rods? Replacement levers with bushes/holes at the bottom and some kind of base frame maybe?

[Skinnylinny]

I intend to have the interlocking tappets mounted horizontally with a slot in them, through which the bottom part of the lever passes, meaning when the lever is pulled, the tappet will slide horizontally (locking permitting!). One end of each of the tappets will have a ramped end which will either depress or release a microswitch. There will definitely be a base frame of some sort, though I've not determined quite what it'll look like yet!

[Nick C]

Have you seen @makeitminiature's videos on his interlocking - he explains it pretty well.

 

Calculating the locking requirements isn't too complex as long as you don't have anything nasty like conditional locking etc. The first step is to write down a list of the actual locking requirements - known as a locking table:

 

Lever | Released by | Locks Normal | Locks Both Ways | Releases  | 
1     | 2           |              |                 |           | 
2     |             | 3, 12, 5     |                 | 1         | 
3     |             | 2            |                 |           | 
4     |             |              | 3               | [8, 9]w/3R|
...

 

Note that there's often less needed than you think - for example, in this case 2 doesn't need to lock any other signal levers as 8/9 are locked by 3 being normal, and 10/20 by 5 being normal - so all the conflicting moves are accounted for. I've over-complicated this example too - you could have 4 only locking 3 reverse (as there's no signalled moves from the platform to the down line), in which case you wouldn't need the conditional locking on 8/9.

 

Once you've got that you can then think about the dog chart (the actual diagram of the physical locking bars, tappets and dogs).

Edited February 13 by Nick C