Turnout construction with plastic components

[hayfield]

I have decided to post my efforts in making a turnout with plastic parts, I was sent a bag of bits from an old K&L kit which I believe was the forerunner to the C&L range.

 

 

I stuck a plan to a piece of hardboard, then covered the plan with repositionable spray mount, once the turnout is finished soak the paper in white spirit and the turnout will just slide off. I use a steel rule to keep the sleepers straight.

 

 

I built the frog assembly off plan (unlike copperclad assembly) using brass shim to keep all the rails in gauge. I learnt by trial and error to tin the shim first. Then trim the shim back to the rail sides.

 

The V assembly was fitted 1st (I should have made it a bit longer)1/2 chairs were fitted where the brass shim is

 

Then the straight stock rail was fitted. I have left 2 chairs off by the check rail, so I can use 2 full chairs to fit it and the 1st 3 slide chairs untill fit the tiebars so they are not damaged when I silder it to the switch blades.

[Donw]

I found that using C&L bits the crossing can move slightly in the chairs made it difficult to set right. My solution was to put a brass screw under the v and solder down on to that. Keeps the frog in the right spot. Also beware if you push gauges against the rail the chairs can distort silghtly. Don't use as much force as you can with copperclad.

Don

[PWSlack]

Proper job. Keep going!

[hayfield]

I found that using C&L bits the crossing can move slightly in the chairs made it difficult to set right. My solution was to put a brass screw under the v and solder down on to that. Keeps the frog in the right spot. Also beware if you push gauges against the rail the chairs can distort silghtly. Don't use as much force as you can with copperclad.

Don

 

Don

 

I am using the method used by many modellers on the V where is soldered together so it stays in gauge and the chairs hold the unit in position. Thanks for the tip re the chairs.

 

 

I have started to fit the curved stock rail, on reflection perhapps I should have put a slight curve in it. The first or is it the last 11 chairs have been stuck in place and now will be left to set hard.

[trisonic]

John,

You use templot? As a quick aside can you tell me if it includes P48?

Thanks, Pete.

[Donw]

Do you put a set into the curved stock rail? I understand that full size practice was to put a set or slight angle where the blades met the stock rail to match the planning angle of the blades. This was to avoid the blades being struck.

Don

[craigwelsh]

Don

I am using the method used by many modellers on the V where is soldered together so it stays in gauge and the chairs hold the unit in position. Thanks for the tip re the chairs.

It can still move, i've got a Exactoscale point kit made up on the workbench that does it.

 

More of an issue though is the check rails moving along in their chairs.

 

To combat both of these i've put a copperclad sleeper through the crossing nose and soldered all rails to brass chairs or brass pins through the sleeper at that point. This guarantees the check rails are live and wont move in relation to the crossing. All rails can expand in both directions still from this point while keeping everything aligned.

[craigwelsh]

Don

I am using the method used by many modellers on the V where is soldered together so it stays in gauge and the chairs hold the unit in position. Thanks for the tip re the chairs.

It can still move, i've got a Exactoscale point kit made up on the workbench that does it.

 

More of an issue though is the check rails moving along in their chairs.

 

To combat both of these i've put a copperclad sleeper through the crossing nose and soldered all rails to brass chairs or brass pins through the sleeper at that point. This guarantees the check rails are live and wont move in relation to the crossing. All rails can expand in both directions still from this point while keeping everything aligned.

 

Do you put a set into the curved stock rail? I understand that full size practice was to put a set or slight angle where the blades met the stock rail to match the planning angle of the blades. This was to avoid the blades being struck.

Don

Yes there should be a set with undercut switches http://www.templot.com/martweb/gs_realtrack.htm#set but you can't really model an undercut switch in 4mm so its better to joggle the stock rails anyway imho and the set isn't really as noticeable then. Filing a groove in the stock rail is a bad move used by some modellers and doesn't run as well as a joggle as well as looking crude.

[marc smith]

I think the use of 1 copperclad sleeper is a quick & easy solution.

 

Personally, regarding the check rails,

I find it very difficult to cut the chairs so that the check rails will sit just right,

and never really got a 100% satisfactory result

 

I previously built points using the brook-smith method

i.e. ply timbers, rivetted, then rails soldered onto rivets....

no problems with the vee, or check rails moving...

 

mind you, I then had to cut each chair in half, and glue them in place...

almost as exciting as ballasting!

 

Also, take care with the sleepers,

myself, and a few other modellers I know did experience some "curling up"

of the sleepers at a later date! - even the thicker sleepers...

Other have told me this has occurred, except when a the point is built in-siturather than on a separate piece of board.

 

Let us know how you get on

Marc

[martin_wynne]

You use Templot? As a quick aside can you tell me if it includes P48?

Hi Pete,

 

Asking this question suggests that you have not properly understood the nature of Templot.

 

It can do any gauge or scale you care to set the dimensions for, it's not a pick-and-place program to select pre-drawn items from a library.

 

However, there is long list of pre-set gauge settings for user convenience, which includes Proto-48:

 

 

regards,

 

Martin.

[PWSlack]

.....put a set into the curved stock rail.....

 

It is correct to do this for bullhead and early flatbottom track, as the blades are straight-planed for the first part (apart from the GWR ones).

 

......full size practice was to put a set or slight angle where the blades met the stock rail to match the planning angle of the blades. This was to avoid the blades being struck.....

 

That is true for straight-cut blades; a straight-cut blade is where no part of the blade fits beneath the head of the adjacent stock rail.

 

There is a double-bend or 'set' in the stock rails to house the blade so that a flange approaching from the toe end of the junction doesn't strike the switch tip until a few inches along the blade. The gauge is wide through the first part of the switch by about 3/8in, tapering away to nil by the second or third P chair.

 

As an alternative to a set, there is a device called the "Mack" switch protector. It is a hardened steel unit bolted through the stock rail a few inches on the toe side of the blade and arranged to give the flange of the wheelset a little nudge away from the tip of the blade so that it misses the tip. The great advantage to these is that, although a wearing component, they can be added to the junction after it is showing to have a problem and it can be replaced between trains.

 

It is not true for undercut switches. There is no set to undercut switch stock rails; an undercut switch is planed to a finer point at the tip than a straight-cut blade, and part of the rail fits underneath the head of the adjacent stock rail.

 

There is no set to the modern vertical-series switches for 113lb flatbottom rail on baseplates on timber or to the bang-up-to-date NR60 switches on concrete bearers; as these switches are planed curved there is no scope for setting the rail and it is merely curved to fit the back of the straight switch blade.

[Donw]

It is correct to do this for bullhead and early flatbottom track, as the blades are straight-planed for the first part (apart from the GWR ones).

 

 

 

That is true for straight-cut blades; a straight-cut blade is where no part of the blade fits beneath the head of the adjacent stock rail.

 

There is a double-bend or 'set' in the stock rails to house the blade so that a flange approaching from the toe end of the junction doesn't strike the switch tip until a few inches along the blade. The gauge is wide through the first part of the switch by about 3/8in, tapering away to nil by the second or third P chair.

 

As an alternative to a set, there is a device called the "Mack" switch protector. It is a hardened steel unit bolted through the stock rail a few inches on the toe side of the blade and arranged to give the flange of the wheelset a little nudge away from the tip of the blade so that it misses the tip. The great advantage to these is that, although a wearing component, they can be added to the junction after it is showing to have a problem and it can be replaced between trains.

 

It is not true for undercut switches. There is no set to undercut switch stock rails; an undercut switch is planed to a finer point at the tip than a straight-cut blade, and part of the rail fits underneath the head of the adjacent stock rail.

 

 

Thanks for that. I had assumed that in pre-group era (pre ww1) the blades would be straight cut. When did the 'Mack' come in please.

Don

[polybear]

 

Also, take care with the sleepers,

myself, and a few other modellers I know did experience some "curling up"

of the sleepers at a later date! - even the thicker sleepers...

Other have told me this has occurred, except when a the point is built in-siturather than on a separate piece of board.

 

Let us know how you get on

Marc

 

I made a turnout using thin plastic sleepering at Missenden Abbey several years ago, under the dirction of Norman Solomon. Brought it home and put it to one side for several weeks; when I next looked at it there was a very distinct upward curve on all sleepers - hence the gauge had changed.

 

I'm now experimenting with different methods of soldered track construction...........

 

Brian

[polybear]

Do you put a set into the curved stock rail? I understand that full size practice was to put a set or slight angle where the blades met the stock rail to match the planning angle of the blades. This was to avoid the blades being struck.

Don

 

 

All is explained here:

 

http://www.templot.com/forum/view_topic.php?id=491&forum_id=1

 

HTH

 

Brian

[martin_wynne]

Thanks for that. I had assumed that in pre-group era (pre ww1) the blades would be straight cut.

Hi Don,

 

As a result of a misleading article in MRJ several years ago there is a common confusion in the hobby between "straight switches", meaning old-style loose-heel switches; and "straight-cut" switches referring to the style of blade tip machining.

 

These are two different things. You can have straight switches with straight-cut or under-cut machining; and curved or semi-curved switches with straight-cut or under-cut machining.

 

Straight-cut switches require a joggle and are normally used in facing locations. Under-cut switches don't require a joggle and are normally used in trailing locations. Except on the GWR and BR(W) where all switches are straight-cut/joggled.

 

More info at: http://www.templot.c...rack.htm#joggle

 

Above info is for bullhead and early flat-bottom track. Modern flat-bottom uses a chamfered style of machining in which the stock rail is also machined, and no joggle is required.

 

regards,

 

Martin.

[hayfield]

Thanks everyone for the replies, when the show is over I will add more

[trisonic]

Hi Pete,

 

Asking this question suggests that you have not properly understood the nature of Templot.

 

 

regards,

 

Martin.

 

 

Martin,

Maybe because I don't own it yet............I'm still stuck in the Ark of Imac - though I'm hopeful of an up to date though used PC from my Wife..............whilst I could amend the Mac I will not because my real life (Composer/Musician) is tied up in it.

 

Best, Pete.

 

 

[PWSlack]

......in pre-group era (pre ww1) the blades would be straight cut. When did the 'Mack' come in.......

 

Pre-grouping switches were generally the short straight type with a pivot arranged at their heel with a loose fishplate. In 2008 there was still a pair of GWR 15ft straight switches installed at Bourne End on the 15ft & 8 junction that leads passenger trains to the Marlow branch, though this switch arrangement is becoming very rare apart from in surviving industrial sidings and heritage railway sidings. Straight-cut, straight planed switches are, or were, fairly common. An undercut straight-planed switch would be as rare as rocking horse droppings.

 

Post 1923, the A, B, C, D, E and F semi-curved switches came into being, where the first two special block chairs, being the 1PLA, 1PRA, 2PLA, 2PRA for an A switch and so-on, have a slide facility like the P chairs in front of them, and the remainder of the special block chairs provide a fixed heel. The switches flex at about the position of the 3-chair. Straight cut semi-curved switches would be found in sidings and facing junctions in running lines on the whole, with undercut in the trailing position on running lines, though it isn't always possible to do this on single lines, obviously. The GWR, as always, was a case apart, using a curved-planed switch for B, C and D, and retaining the 30ft straight switch for longer junctions, according to British Railway Track edition 2.

 

The Mack switch protector appears in permanent way vendor catalogues dated 1969. There is insufficient information to hand to be able to put boundaries on the date. The Mack would be typically about 0.5*0.5*1mm in 4mm scale, would fit on the web on the inside of the stock rail and, given the simplifications that many put into their track construction, would rarely be found on a model.

 

It isn't practicable to model undercut switches in the smaller scales.

 

There are illustrations to hand from a number of booklets; sadly, as these are copyright to the original publishers, they cannot appear in RMWeb. The solution is to look for copies over time in specialised booksellers' collections and, if possible, obtain a copy of "the Bullhead Supplement" from the Permanent Way Institution; this publication was prepared to assist those involved in track reconstruction for heritage railways in the British Isles, though there is much in there of an explantory nature that finescale modellers will find invaluable.

 

There is a publication on GWR junction design available running to over ninety pages, which is of little specific interest here, and the LNER Study Group also has publications on LNER junction design that use original standardised data from LNER design offices. The LNER, being a bit of a cheapskate ( ), did not adopt the long bullhead F switch, preferring to run its trains at lower speeds - presumably until the introduction of the 225 on the East Coast Main Line.......

 

There is currently an excellent example of an E&14 + D&14 bullhead crossover to be studied at the east end of Weybourne Station on the North Norfolk Railway, and sweet perfection in ex-SR bullhead materials at the north end of Horsted Keynes on the Bluebell Railway, among other places, if a track pass or a track-competent volunteer companion can be found to enable closer inspection.

 

Further useful data can be found in the EM Gauge Society's manual sheets on the topic.

[martin_wynne]

An undercut straight-planed switch would be as rare as rocking horse droppings.

I'm a bit puzzled why you say that. The REA bullhead designs all use semi-curved switch geometry with straight planing, and undercut switches were common (i.e. no joggle needed, for trailing locations). They are illustrated in BRT3. Here is one such in platform 1 at Kidderminster on the SVR. The very delicate nature of the switch tips (points) is very evident. This is a left-hand switch -- there is clearly no joggle on the left-hand stock rail:

 

 

 

regards,

 

Martin.

[Neil]

I too have experienced the curly sleeper syndrome. I now use ply sleepers sticking the chairs with solvent. I've chosen not to use copper clad sleepers at strategic locations because I like the look of the died timber and don't want to compromise that. The only problem I've experienced is the stock rails tending to wander inwards where they are supported by slide chairs. A brass pin half way along the slide chair stretch once laid and ballasted soon cured that. Oh and I don't joggle the curved stock rail, but I do let it drift a little wide to gauge around the tie bar.

[Donw]

I never noticed any problems with sleepers curling up. But I usually lay my pointwork in situ sticking the sleepers down fist with PVA. And I usually ballast it fairly quickly. Perhaps thats the difference.

Don

[Bernard Lamb]

I made a turnout using thin plastic sleepering at Missenden Abbey several years ago, under the dirction of Norman Solomon. Brought it home and put it to one side for several weeks; when I next looked at it there was a very distinct upward curve on all sleepers - hence the gauge had changed.

Brian

 

I thought that you needed to build this type of track in situ. Build it glued to a firm supported base and there should be no problems. If the odd sleeper is precurled then it can be rejected. If you build in situ you can also solder the vital parts to screws or pins fixed to the baseboard. As others have said this does improve the stability of a turnout. Ballasting before fitting any rails must also be regarded as a big bonus when using this method.

Bernard

[Stephen Freeman]

I think using solvent for construction is the root of the problem. If you use one of the special super-glues - designed for plastic (e.g. Plasti-Zap) , I doubt you will have any problems.

[craigwelsh]

Curly sleepers dont happen with full height Exactoscale sleepers, the turnout on my bench is 6 years old now and the gauges still slip onto the rails correctly. That one being from a kit doesn't have the copperclad reinforcing either.

 

I'd agree with Neil that using a copperclad sleeper with ply can spoil the look though it is useful to use one under the switch blades if fitting a sole plate.

[hayfield]

Thanks for all the input.

 

Thin sleepers do tend to curl up if not stuck well enough to the base board as did the early SMP sleeper bases. Thanks for the tip about the stock rails where the slide chairs are.

 

I find that the finer the scale the need to put a set into the curved stock rail increases.

 

Too tired to do any work on the turnout tonight, will have a close look at the Exacto scale parts at the Watford Show tomorrow