Trackwork options for newbie

[Tim V]

On Clutton (built some 20 odd years ago), I used the Studiolith TOUs, but modified per the Peter Cross article in MRJ 20. No lifting of the switches.

For the stretchers, I used the ingenious idea of the North London Group, written up by the late Mike Sargent of dummy ones in MRC March 1982. Gets completely round the problem of functional stretchers breaking!

[grovenor-2685]

Which leaves me a bit puzzled. Because I can well remember many layouts where the holes for the dropper pins were inside the 4-foot and directly below the blade points. Howard's comment about blades lifting would seem to confirm my recollection of the problems with them.

The spacing of the tubes in the TOU gives the result as shown in your diagram, and, it does consider the vertical restraint. The other problems mentioned by Howard do inded exist, they stem from the tubes not having enough stiffness making it very difficult to control the throw, use of the hairgrip gauges for assembly as per instructions only works if the movement is free enough to avoid bending the tubes. This problem is largely avoided in the newer 'Exactoscale' version by using much thicker and hence stiffer tubes. With the Studiolith version it is best controlled, by a link between the blades, either a cosmetic stretcher or a hidden link at ballast level. The catching on rivets which can exascerbate the problem is simply avoided by fitting slide chairs.
Regards
Keith

[allanferguson]

Which leaves me a bit puzzled. Because I can well remember many layouts where the holes for the dropper pins were inside the 4-foot and directly below the blade points.

regards,

Martin.

I used these quite a bit in the pre-history period.... Once fixed through the advised baseboard of 6mm ply + 3mm cork they could work very well. They would have worked a lot better if we'd had proper slide chairs. The advice was to drill, if I recall, 4mm holes centred about 1mm outside the rails. Well, fine if you could think that far ahead, but most of us didn't, and the advice then was to drill 1mm holes just inside the rails, then enlarge them from below to 6mm. which is why you saw so many big holes in the switchblade area. it was possible, but very difficult, to cover the hole with paper, then ballast, as advised.

Nevertheless the concept was good, and I would use them again, with some modifications.

Allan F

[Ade]

Good debate chaps - keep it up! Glad to see that Ade is still with us and hopefully feeling helped

Yep, I'm hanging on in there! Great stuff, chaps.

Well, it all depends what you mean by "modern"!

Ha ha! Fair enough, I wasn't very precise. I mean post-war. (Yes, yes, I know, even that is vague )

There is a very thorough expose on flat-bottomed track by Colin Ceraig at http://www.mmrs.org.uk/technical/track.html although it currently stops at new track of 2004.

Yes, I've read it - fascinating stuff.

I have a note that I copied from somewhere re :
That therefore means that the choice we have in 4mm scale is:
• C&L - representing the E1/4 - manufactured 1944 – 1954 ( Sleepers - 'Dowmac' concrete (for bullhead rail) 4SL104A)
• Exactoscale - representing the F27 - manufactured 1969 - 2003 (Concrete sleeper FastTrack for FB rail E4FT 103A)
• Peco - representing the F40 - manufactured 1983 - 1999 (not much use for P4!)
and of course there are Colin Craig's parts.

Yes, Martin, that helps a lot. Thanks very much!

[Ade]

Back to TOUs and tiebars (though more focussed on tiebars than TOUs)... I'm going to try to summarise where the debate has got to so far in terms of options.

1. One possible TOU option - referred to as the Keith Norgrove design, based on the exactoscale tortoise adapter driven by a servo, mentioned by John Mac here.

2. Ambis stretcher bar avoiding the use of PCB, as described by Howard in Scalefour News 181, perhaps more prototypical than some other methods.

3. Alternative copper clad bar method, as described by Mike Norris in Scalefour News 181, which Howard recommended as a solid, effective method for a beginner though less prototypical.

4. David Thorpe mentions using Masobits tiebars and his satisfaction with them on his current layout, though he wonders about their potential fragility under heavy use. Terry Bendall speaks up in favour of Masobits as functional tiebars, for their prototypical authenticity and look and, in his experience, reliable performance under heavy use conditions. John Duffy points out that not all railway companies used flat bar mechanisms. So, perhaps one can conclude that the answer to whether Masobits are the closest to prototype is: "depends on the prototype".

5. PALM TOU's with Ambis cranks and unmodified Ambis stretcher bars, mentioned by Keith with accompanying videos of them in use on a demo board.

6. Mark Tatlow's PCB stretcher method, demonstrated here.

7. "Old" Studiolith stretcher bars, discussed by Keith and others. Overall impression (mine) is that these have fallen out of favour and have been superseded by better methods, though they work fine for some if properly installed and set up.

8. Tim V mentions successful use of Studiolith TOUs, but modified per the Peter Cross article in MRJ 20, resulting in no lifting of the switches.

Have I summarised the options correctly? (If anyone feels I have mis-represented something, please let me know and I'll edit accordingly.)

Edited: item 5 updated
Edited: item 8 added

[grovenor-2685]

5. PALM TOU's with Ambis cranks, mentioned by Keith with accompanying videos of them in use on a demo board. (However, it's not entirely clear to me which stretcher bars he was using.)

That one is an Ambis stretcher built with PCB as designed.
Keith

[Ade]

That one is an Ambis stretcher built with PCB as designed.
Keith

Thanks, Keith. Updated accordingly.

[Russ Elliott]

Ade - some TOU information is given in Somersham. These TOUs are homemade efforts. The 0.7mm droppers do not crank under the stock rail, but go straight up from their underboard actuator tubes to the switchblades. The switchblades are therefore not constrained from 'lifting', which is perhaps trusting to luck to some extent, but I haven't as yet experienced any trouble. There are no stretcher bars (and probably never will get round tuit, if only for a fear of introducing too much rigidity between the blade pairs - I feel more comfortable if each blade has a degree of independence of movement from its partner, and such independence becomes an absolute requirement for double slip blade sets).

I found the key to keeping the gentle sideways force on the blades just enough was to ensure the actuator travelled only for the distance necessary in the TOU - this was achieved by taking up the slack in the operating movement from the point motor by use of crank reduction and gentle Z-loop tensioners. For a 1.75mm blade movement, I reckoned on an approximate 2mm TOU actuator movement, the dropper being just sloppy enough in its tube (I think a 0.9mm bore, with an outside diameter, approx 1/16" ISTR, that makes them more rigid than a conventional hypodermic tube size) but just bendy enough to keep the blades gently pressured against the stock rails. The 'bendy enough' reflects the strength of the dropper and its fit in the tube bore, so is an empirical value depending on what size of dropper wire is used, and how much sticks out of the top of the tube, and the length and strength of the tube.

Excessive lateral movement at the TOU can tend to produce a tilt as Howard drew *, which I have witnessed before in other applications if the TOU movement is too much or not positioned correctly.

On Somersham, any grot falling through the dropper hole falls freely downward, and does not gum up the TOU mechanism, unlike the previous (Studiolith-inspired) ones on Green Street, which required splash plates.

Rivets where present on slide chair positions are ground away (at least their protruding edges) and plastic slide chair plates are used, but I like to thin these a whisker, preferring the blade not to be sliding in contact with anything (maybe one or two slide chair tops at the toe end) - I feel the vertical strength of our rail is perfectly adequate.

This reply started off as a one-liner, but, err, grew a bit!


* How were you driving them, Howard?

[Ade]

Ade - some TOU information is given in Somersham.

Excellent. Thanks for that, Russ.

This reply started off as a one-liner, but, err, grew a bit!

It's all good stuff and one can never have too much information. Thanks!

[JFS]

* How were you driving them, Howard?

Hello Russ,

Mostly mechanically, via bits of piano wire and linkages of questionable quality - and you are quite right to ask as therein lies a multitude of pitfalls!! As you say, any tendency to "over-drive" them causes the tipping. Of course, in those days, Tortoises were a species of land-dwelling turtle... So probably worth mentioning to newbies that if you use a "stall" motor (ieTortoise, Cobalt) you need to provide adjustable stops and not rely on the switches to do the job.

I fully agree that anything which might cause the blades to stick (ie either the slide chairs, or indeed the dropper wire rubbing on the underside of the stock rail) is a real cause of potential pain and using much stronger dropper as you have done and as per Mark's solution above are ways to minimise this. Such factors are much less of an issue with an over-baseboard drive which is virtually in-line with the blades

My goodness - looking through this lot, it is amazing we ever get anything to run reliably

Best Wishes,

[Ade]

My goodness - looking through this lot, it is amazing we ever get anything to run reliably

I was starting to wonder the same thing...

[David Knight]

Dave Booth came up with a variation on the Studiolith design that was in MRJ 139 that I have used and found to be most satisfactory. I use it for wire in tube but the original design was for a Tortoise IIRC.

working bits.jpg

The whole thing is made up from Plastruct square tube and angle plus brass tube. The sizes given in the article are inaccurate but can be figured out easily enough.

top view.jpg

The droppers are L-shaped brass rod soldered to the underside of the rail and do double duty, keeping the blades from rising up and allow shifting back and forth as required. The turnout illustrated is my first P4 turnout on a test track built lo these many years ago so leaves much to be desired cosmetically, but it still works.

Cheers,

David

[Martin Wynne]

The turnout illustrated is my first P4 turnout on a test track built lo these many years ago so leaves much to be desired cosmetically, but it still works.

Hi David,

I'm surprised, because the blade opening is far too small (a common P4 mistake). It should be 4.25" scale (1.42mm) at the tip (and maybe a bit more for the overscale P4 flangeway gaps). That's more than one and a half rail-widths, whereas your gap at the tip is clearly less than a rail width. If you don't open the tip far enough the wheels may catch the tip, and it's difficult to get a full flangeway clearance all along behind the open blade. The unused area of the slide chairs is showing that something is not right.

Not being critical, just warning beginners not to copy this.

Martin.

[David Knight]

Fair point Martin. I have done better since

Cheers,

David

[Terry Bendall]

I've been musing about options for modelling modern FB rail and concrete sleepers.

That therefore means that the choice we have in 4mm scale is:
• C&L - representing the E1/4 - manufactured 1944 – 1954 ( Sleepers - 'Dowmac' concrete (for bullhead rail) 4SL104A)
• Exactoscale - representing the F27 - manufactured 1969 - 2003 (Concrete sleeper FastTrack for FB rail E4FT 103A)

I thought, but may well be mistaken, that the C&L concrete sleeper track was for flat bottom rail.

I have used the Exactoscale fast track "concrete" sleeper bases but in my view the rail fixings are a bit undernourished.

The Colin Craig FB fixings are designed for use with copper clad sleepers and can be PAN11 baseplates which are white metal castings glued in place after the rail is soldered to baseplates which give the 1 in 20 inclination or using BR1 or BR2 type fixings which are made from two etched brass components. All are a bit time consuming to use but look very good when done but the sleepers of course are intended to represet wooden ones rather than concrete.

Terry Bendall

[Phil O]

I've been musing about options for modelling modern FB rail and concrete sleepers.

That therefore means that the choice we have in 4mm scale is:
• C&L - representing the E1/4 - manufactured 1944 – 1954 ( Sleepers - 'Dowmac' concrete (for bullhead rail) 4SL104A)
• Exactoscale - representing the F27 - manufactured 1969 - 2003 (Concrete sleeper FastTrack for FB rail E4FT 103A)

I thought, but may well be mistaken, that the C&L concrete sleeper track was for flat bottom rail.

I have used the Exactoscale fast track "concrete" sleeper bases but in my view the rail fixings are a bit undernourished.

The Colin Craig FB fixings are designed for use with copper clad sleepers and can be PAN11 baseplates which are white metal castings glued in place after the rail is soldered to baseplates which give the 1 in 20 inclination or using BR1 or BR2 type fixings which are made from two etched brass components. All are a bit time consuming to use but look very good when done but the sleepers of course are intended to represet wooden ones rather than concrete.

Terry Bendall

Hi Terry

Here is a link to some photo's of B/H rail on concrete sleepers.

https://www.google.co.uk/search?q=bullh ... B626%3B180

There are a few panels on the ESR, you can see some of them from Maesdown Road overbridge, not far off the A361 at Doulting.

Cheers Phil

[grovenor-2685]

I thought, but may well be mistaken, that the C&L concrete sleeper track was for flat bottom rail

I believe that Martin M is correct in this case, the C&L sleeperr has a flat top surface for bolting chairs on.
The Peco sleeper correctly has the top surface inclined at 1:20 for FB rail. The problem in this case being that there are no suitable rail fixings unless something from Colin Craig's range could be adapted. The Peco clips are devoid of detail and hold the chair much to high off the sleeper.
Regards
Keith

[Martin Wynne]

A topic on RMweb has just reminded me of something I tried a long time ago. Nowadays the availability of moulded chairs may make it worth considering for beginners. You can build initially with the cheapness and adjustability of copper-clad, and then only later fit cosmetic chairs if desired. For this to be possible the rails need to be lifted above the surface of the timber (strictly by a scale 1.75", the thickness of the base of a chair casting, or 0.58mm -- but anything is better than nothing).

From an old topic on RMweb: http://www.rmweb.co.uk/forum/viewtopic. ... &start=125

From which:



In another world a long time ago I once did something very similar using single-sided Vero pins.

It was much quicker to do than the above looks to be. Use a softish workboard material under the template. Drill 1mm hole with minidrill, through copper-clad and into board, abrade off any copper burrs, and push in pin. They have ribs under the head and are a firm push fit. No need to solder them separately -- do it all in one go when you are soldering the rail. Prise up the finished the turnout from the workboard and trim off flush the protruding pins from the underside. You could leave a few for invisible electrical connections. Make sure when laying that nothing can short the underside of the pins (as you would with Brook-Smith rivets).

We are talking 40 years ago, and much to my surprise the Vero pins are still available, and not desperately expensive:

http://uk.rs-online.com/web/p/terminal-posts/6319596/

Here's the manufacturer's drawing:

http://docs-europe.electrocomponents.co ... e578ba.pdf

Templot can produce a drilling template showing rail centre-lines over timber centre-lines (generator > generator settings > rails > rail head centre-lines only). Print on tracing paper and lay over the copper-clad timbers:



Current topic on RMweb: http://www.rmweb.co.uk/community/index. ... try1560435

regards,

Martin.

[Re6/6]

They don't take that long to make Martin.

I use the 20 thou waste strips from Brassmasters f/b baseplate frets. They are as near as the same thickness as the plastic web under the Exacto chairs that I use. With practice very small and even sized pieces can be created. I keep a supply for all future track making.

As Tim M has said on RMw I would find drilling holes for pins a bigger chore than doing it this way!

[waveydavey]

I thought, but may well be mistaken, that the C&L concrete sleeper track was for flat bottom rail

I believe that Martin M is correct in this case, the C&L sleeperr has a flat top surface for bolting chairs on.
The Peco sleeper correctly has the top surface inclined at 1:20 for FB rail. The problem in this case being that there are no suitable rail fixings unless something from Colin Craig's range could be adapted. The Peco clips are devoid of detail and hold the chair much to high off the sleeper.
Regards
Keith

The C&L concrete sleepers can be used with both BH and FB rail.

With BH rail and C&L GWR 2 bolt chairs they can be used to represent the concrete sleepered BH track that BR laid a lot of under the modernisation plan. It was found to give a poor ride and tended to be removed from the main line quite quickly. There is still some on the Blyth and Tyne railway and may possibly still be some at Applehirst Junction area north of Doncaster although I've not been that way for a while, both low speed sections of track with permissable speeds less than 45mph. There is still a great deal of it around on depots and yards.
With Peco IL-112 Pandrol baseplates and the C&L concrete sleepers (and 8'6" wooden sleepers if you like) you can represent a type of FB track that is still very common on secondary mainlines. The only problem with this is that the Pandrol clip on the Peco baseplate is overscale by about 60%.

C&L also do a ST baseplate for FB rail. I may be wrong but I'm fairly sure they were only ever used on FB wooden sleepered pointwork. By which I mean that I've never noticed them on plain line but have seen plenty on P+C.

Cheers

David

[grovenor-2685]

the concrete sleepered BH track that BR laid a lot of under the modernisation plan.

i could be wrong too, but I don't think much if any of that type of track was laid in the 'modernisation plan' I think it predated that plan and was larcely a wartime and immediate post war expedient due to the timber shortages. Similarly I think that use of baseplates on concrete sleepers for FB was rather limited, although pics of both Mills and Pandrol examples are in the links below. The modernisation plan effort went into the direct fastening designs of which there were quite a variety before standardising on pandrols. I do remember quite a bit of relaying on the West Coast using baseplates on timber, Jarrah IIRC, with the sleeper spacing significantly closer than the concrete being laid at the same time (early '60s).
Unfortunately no pic of an ST baseplate here http://www.scalefour.org/resources/trackdetails02.html but there is here http://www.mmrs.org.uk/technical/track.html supporting the main use being for S&C.
Keith

[waveydavey]

I formed the opinion that the concrete sleepered BH track was a Modernisation Plan thing because there is so much of it at locations built under said plan. Thornaby Depot, Tyne and Tees Yards being the ones I have spent the most time studying although I've seen it in most other places I visit in my day job. It may well have pre dated the plan and the track I've seen could have been recovered from other locations for reuse. I'll check the casting dates of the chairs next time I see some.

Pandrol baseplates on both concrete and wooden sleepers are still common enough for me to say their use was a bit more than 'limited'. I see sections of such track on most of the lines I drive over although it is slowly being replaced with more modern track as time goes by. Simlarly, BR1, BR2 and Mills Clipped track is still very common too. You probably wouldn't see any on 125mph main lines but you'd see plenty of it on adjacent slow lines.

Cheers

David

[Ade]

Regarding FB track, I've just stumbled across Terry Bendall's useful article in Scalefour News 174. Very interesting indeed!

[waveydavey]

i could be wrong too, but I don't think much if any of that type of track was laid in the 'modernisation plan' I think it predated that plan and was larcely a wartime and immediate post war expedient due to the timber shortages.

Apologies to Ade for keeping this going so far off topic.

At Boulby Potash Mine last night I spotted a pile of redundant concrete sleepers with 2 bolt BH chairs (the branch from Crag Hall was fully relaid with FB track by Cleveland Potash in stages 7-10 years ago although there is still wooden sleepered BH track in the yard at Boulby). It was too dark to get a decent photo but I was able to read the casting dates on the chairs and most that I could make out were 9/54 although there were examples of 12/52 and one from 1956. Clearly then this track must predate the 1955 Modernisation Plan but can be assumed to have continued to be laid into the early years of it.

Cheers

David

[Alan Turner]

We use quite a lot of this track type on the SVR.

IMAG0325.jpg

IMAG0324.jpg

IMAG0323.jpg

IMAG0326.jpg

regards

Alan