Crossing Vees.

[Gordon A]

As I am in the process of building a turnout using plywood sleepers, P4 Track and C&L components I have been looking closely at the prototype, hence my previous pictures of the switch blades.

 

Looking at the C&L pre-assembled crossing vee and wing rails I noted that the ralis are vertical.

Assuming the real thing took a similar approach, I asked the question of one or two people where did the the transition from vertical to the 1:20 cant of the rail on plain track take place.

 

Not totally happy with the answers I received I decided to visit my local heritage railway, where I am a volunteer for a closer look.

 

I have taken a few pictures to try to show what I found:

A couple of shots looking along the rail head towards the point vee.

Note there is no apparent change in cant.

 A couple of pictures of the crossing vee.

 

My conclusion is that the rail used in the crossing vee is assembled whith the correct 1:20 cant to match the plain track. I am not sure how well my pictures show this.

 

Comments from anyone with first hand knowledge appreciated.

 

If I am right how do we file the rails for the vee?

 

Or am I totally wrong?

 

Gordon A

Bristol

 

 

 

 

 

 

 

[Grovenor]

Comments from anyone with first hand knowledge appreciated.

For normal UK bullhead track, you are correct, the rail inclination (not cant) is carried through the crossing.

If I am right how do we file the rails for the vee?

 

Mostly we just build it vertical and wait for any criticism, when we get any we give the critic a challenge!

If you want to try it  its just a matter of filing the rail at the appropriate angle, or, since you can only see the fit at the top, filing at a larger angle to give clearance at the foot then making a fixture to hold it at the required angle while soldering.  Don't forget you also need to bend the wing rail very craftily so the end does not stick up in the air.

 

Early versions of Flat bottom turnouts are done similarly, then in the 60s, co-incident with the move to 1432 mm gauge the rail in FB turnouts was changed to vertical. The vertical range is still in use for 113lb rail but turnouts made with UIC60 rail have reverted to inclined rail and 1435 mm gauge. Of course using onepiece cast crossings the problem of making  crossings with inclined rail does not arise.

Regards

Keith

[hayfield]

Building model trackwork is a compromise. If you go back to P4 days the rail was soldered vertically as per copperclad construction today. I have no doubt that there are some purists who build their trackwork with inclination through the crossings. But I guess for most it is a step to far.

 

One thing to watch out for with plastic chairs, is that some track gauges hold the rail upright when you remove the gauges the rail reverts from vertical to the 1-20 inclination thus narrowing the gauge

[martin_wynne]

Hi Gordon,

 

For bullhead track the rails forming the vee nose are vertical where they are spliced together. There is a twist in the rails, usually between the B and C chairs (i.e. opposite the end of the wing rails) so that the rest of the rail is inclined at 1:20. It is a tricky twist to make, because the gauge face of the rail has to remain in a straight line. The foot of the rail is twisted outwards while holding the head straight. You can see the twist if you go looking for it, but otherwise it generally goes unnoticed.

 

Also the check rails are vertical in bullhead track, to provide the full depth of the head as a wear face against the back of the wheels.

 

regards,

 

Martin.

[HAB]

Gordon,

 

I agree with Keith, but would add a bit.  If you want to use plastic chairs functionally (and why would you not?) then this question of rail inclination suddenly becomes quite important because the chairs do incorporate the inclination therefore, you do have to think about what to do about it - otherwise, any vertical rail must be fighting the chairs to some extent.

 

I would go a step further and add that, IMHO, methods which work very well for solder and rivet track are not much help for plastic chaired track.

 

My solution (which works for me but which will not be to everyone's taste) is to follow the prototype by building all the switches and crossings as sub-assemblies, then assemble them only when I am building the track. Thus, "temporary" chairs are threaded on to the pre-prepared rails to hold them at the correct inclination whilst soldering.  I use slips of nickel silver (22thou etch fret waste) under the rails at all the timber positions.

 

Here are a few pics to illustrate what I mean

 

 

 

I build the assemblies on a spare template (created in Templot so I know it is identical to the one I will build the track on)

 

 

I do the same for switches and I include the switch anchor to hold the thing together.

 

 

The benefit of all this is that you can see where the rail inclination needs to be straightened out and deal with it. - before you ever commit anything to a piece of track

 

Here was my attempt at laying my sub-assemblies together - you can see a fair few places where the rails are in need of a tweak!

 

 

I also use the opportunity of working in this way to ballast the sleepers before I locate the rails -

 

 

 In this one, you can see all the sub assemblies (with chairs threaded and droppers attached) ready for glueing down - needless to say, they have all been very carefully tested for fit - and thus just need fitting to gauge before letting loose with the solvent.

 

 

And eventually, it looks like trackwork...

 

 

Now, having said all that lot, I don't know anyone else who does it my way so I could just be that I am out of step with the rest of the army!

 

I have written up the method in a bit more depth here if you feel like giving it a go -

 

http://www.scalefour.org/forum/viewtopic.php?f=78&t=2591

 

And there are a few more pics here;-

 

http://www.scalefour.org/forum/viewtopic.php?f=78&t=1342

 

 

BUT - if you have not built much functionally chaired track before, my advice would be to try a simple plank first!

 

 

Hope that helps,

 

Good Luck!

 

 

 

 

 

 

 

 

[Welly]

^^^

For one moment, I thought I was looking at a photo of real trackwork!

 

Back on topic, I won't bother about the 1:20 inclination of the rails in 4mm scale as it cannot be seen! But the info is interesting.

[HAB]

^^^

For one moment, I thought I was looking at a photo of real trackwork!

 

Back on topic, I won't bother about the 1:20 inclination of the rails in 4mm scale as it cannot be seen! But the info is interesting.

 

Thanks for the kind words!

 

Whether you can see it or not depends on how closely you look

 

But my point was really more about the geometry - you can't ignore it IF you use functional plastic chairs - they put it in for you.  If you think about how the chairs hold the rail, then, in this pic, rail "A" leans towards us and rail "B" leans away from us -

 

 

thus where they cross, (in the crossing) the difference is 1 in 10 - which is a fair old bit and not to be ignored - and in the case of the wing rails, they cock upwards a fair bit if you don't twist them to be vertical at the knuckle. No wonder there are so many derailments in P4 if people ignore such matters

 

Cheers,

[Gordon A]

Thank you chaps.

 

I find it interesting that I have not seen this particular topic mentioned in any track books.

Your replies have been very interesting and helpful.

 

I will try twisting the rails along the lines that Martin has mentioned.

 

Gordon A

Bristol

[ozzyo]

For normal UK bullhead track, you are correct, the rail inclination (not cant) is carried through the crossing.

 

Mostly we just build it vertical and wait for any criticism, when we get any we give the critic a challenge!

If you want to try it  its just a matter of filing the rail at the appropriate angle, or, since you can only see the fit at the top, filing at a larger angle to give clearance at the foot then making a fixture to hold it at the required angle while soldering.  Don't forget you also need to bend the wing rail very craftily so the end does not stick up in the air.

I have no doubt that there are some purists who build their trackwork with inclination through the crossings. But I guess for most it is a step to far.

One thing to watch out for with plastic chairs, is that some track gauges hold the rail upright when you remove the gauges the rail reverts from vertical to the 1-20 inclination thus narrowing the gauge

Back on topic, I won't bother about the 1:20 inclination of the rails in 4mm scale as it cannot be seen! But the info is interesting.

But my point was really more about the geometry - you can't ignore it IF you use functional plastic chairs - they put it in for you.  If you think about how the chairs hold the rail, then, in this pic, rail "A" leans towards us and rail "B" leans away from us -thus where they cross, (in the crossing) the difference is 1 in 10 - which is a fair old bit and not to be ignored - and in the case of the wing rails, they cock upwards a fair bit if you don't twist them to be vertical at the knuckle. No wonder there are so many derailments in P4 if people ignore such matters

 

Hello all,

 

the 1;20 inclination will be kept on the full sized rail up to the crossing nose due to the rail being machined and then bolted together using all of the special chairs that the real railway has to play with.

 

There is no reason why we can't do it all we have to do is take more off the bottom of the rail, assuming that the rail head and base are the same width (this would be for code 75 rail, 0.00375" [0.095mm], or for code 100, 0.005" [0.127mm]). The bend on the wing rail would be a bit to bring it back down to flat with the top of the running rail. As far as I can tell you should aim to lose the difference in the angle at the start of the wing rail. 

 

The spring back in the rail head  with using a track gauge should not be that much of a problem "if" the gauge only holds the rail head, as the max. that you could get using code 75 rail would be 0.0075" [0.19mm] (that is assuming that both rails are brought to vertical) I would think that in P4 etc. that you have more clearance than that between the wheel flanges and the track gauge.

 

In the last quote, it is a bit misleading to say that the difference is 1;10 as the two rails never meet. The matching rail for 'A' should still be at 1;20 and the matching rail for 'B' should still be at 1;20. But if the vee has the two rails at 1;20 at the point of the vee (assuming that the rail head is 0.040" wide you should have a peak of 0.002" on the diverging running line). But when you look at how a real vee is made the diverging line is spliced in to the main line to most of its width so in a model the 'bump' would be about 0.001" (if that) on the diverging line.  

 

OzzyO.

 

EDIT for PS. if you look at the last photo in post 1 and look at the wear pattern on the main running line (the rusty one) you can see the the outer edge of the rail has a small step worn in to it, so this is showing that the rail is inclined at this point. Also when you look at the rust at the point of the vee it's only part worn away, that says to me that the rail top is inclined. 

[HAB]

 

 

Hello all,

 

 

In the last quote, it is a bit misleading to say that the difference is 1;10 as the two rails never meet. The matching rail for 'A' should still be at 1;20 and the matching rail for 'B' should still be at 1;20. But if the vee has the two rails at 1;20 at the point of the vee (assuming that the rail head is 0.040" wide you should have a peak of 0.002" on the diverging running line). But when you look at how a real vee is made the diverging line is spliced in to the main line to most of its width so in a model the 'bump' would be about 0.001" (if that) on the diverging line.  

 

 

Hello OzzyO

 

Indeed, the two rails don't physically meet, but somewhere an allowance for the inclination must be made - hence my statement that a twist is needed at the knuckle.  If you think about bending a wing rail into a piece of vertical rail, the wing rail will sit flat on your bench.  If you now incline the rail at 1:20, the wing rail must be "cocked-up" at that angle. In practice (and I built the track in the pic, so this is experience, rather than "theory") you just need to put a slight HORIZONTAL twist in the rail so that it sits level at the crossing and, in fact, that is exactly what the prototype did.

 

What prototype references do you have to hand?  Just looking in the GW Common Crossing Chair drawings, it shows the wings rails at 1:20 but both crossing rails vertical as far out as the 4C position (ie beyond the machining, but within the length of the wing rails) but inclined by the 5C position.  I don't have detailed drawings of REA chairs to hand.

 

Have you built much track using plastic chairs???    If you have, you will surely have experienced the effect I am talking about.  If you are not using plastic chairs, the whole debate is academic

 

Just BTW, I personally think that correctly inclined rail in scale chairs looks fabulous (you CAN see the difference!) and I hope that the pic of my double slip above shows what I mean - I am thinking hard about how to improve it - all suggestions welcome - but I confess I have not had a mike on it to measure the "bump"

 

Best wishes,

[ozzyo]

Hello all,

 

the 1;20 inclination will be kept on the full sized rail up to the crossing nose due to the rail being machined and then bolted together using all of the special chairs that the real railway has to play with.

 

There is no reason why we can't do it all we have to do is take more off the bottom of the rail, assuming that the rail head and base are the same width (this would be for code 75 rail, 0.00375" [0.095mm], or for code 100, 0.005" [0.127mm]). The bend on the wing rail would be a bit to bring it back down to flat with the top of the running rail. As far as I can tell you should aim to lose the difference in the angle at the start of the wing rail. 

 

The spring back in the rail head  with using a track gauge should not be that much of a problem "if" the gauge only holds the rail head, as the max. that you could get using code 75 rail would be 0.0075" [0.19mm] (that is assuming that both rails are brought to vertical) I would think that in P4 etc. that you have more clearance than that between the wheel flanges and the track gauge.

 

In the last quote, it is a bit misleading to say that the difference is 1;10 as the two rails never meet. The matching rail for 'A' should still be at 1;20 and the matching rail for 'B' should still be at 1;20. But if the vee has the two rails at 1;20 at the point of the vee (assuming that the rail head is 0.040" wide you should have a peak of 0.002" on the diverging running line). But when you look at how a real vee is made the diverging line is spliced in to the main line to most of its width so in a model the 'bump' would be about 0.001" (if that) on the diverging line.  

 

OzzyO.

 

EDIT for PS. if you look at the last photo in post 1 and look at the wear pattern on the main running line (the rusty one) you can see the the outer edge of the rail has a small step worn in to it, so this is showing that the rail is inclined at this point. Also when you look at the rust at the point of the vee it's only part worn away, that says to me that the rail top is inclined. 

 

Hello OzzyO

 

Indeed, the two rails don't physically meet, but somewhere an allowance for the inclination must be made - hence my statement that a twist is needed at the knuckle.  If you think about bending a wing rail into a piece of vertical rail, the wing rail will sit flat on your bench.  If you now incline the rail at 1:20, the wing rail must be "cocked-up" at that angle. In practice (and I built the track in the pic, so this is experience, rather than "theory") you just need to put a slight HORIZONTAL twist in the rail so that it sits level at the crossing and, in fact, that is exactly what the prototype did.

 

What prototype references do you have to hand?  Just looking in the GW Common Crossing Chair drawings, it shows the wings rails at 1:20 but both crossing rails vertical as far out as the 4C position (ie beyond the machining, but within the length of the wing rails) but inclined by the 5C position.  I don't have detailed drawings of REA chairs to hand.

 

Have you built much track using plastic chairs???    If you have, you will surely have experienced the effect I am talking about.  If you are not using plastic chairs, the whole debate is academic

 

Just BTW, I personally think that correctly inclined rail in scale chairs looks fabulous (you CAN see the difference!) and I hope that the pic of my double slip above shows what I mean - I am thinking hard about how to improve it - all suggestions welcome - but I confess I have not had a mike on it to measure the "bump"

 

Best wishes,

 

Hello HAB all,

 

in your first paragraph you mention that a twist is needed at the knuckle, that was what I was saying in my last two sentences in my second paragraph (The bend on the wing rail would be a bit to bring it back down to flat with the running rail. As far as I can tell you should aim to loose the difference in the angle at the start of the wing rail).

 

Your question in para. two, I was working from memory, it's not the best way to answer questions but some times you do.  If you look at the photo below you will see that the main running line runs off to the left (the one with the light rust on it), when you look at the diverging line it has a full shine on it apart from a small  area that matches the part of the main route that has a shine on it. Then when you look at the crossing nose you can see that only half the nose has a shine to it.

The above wear patterns on the vee says to me that the rail head as inclination of 1;20 on them, if the rail head was still at 90deg. to the rail side you would only see the bright part of the rail on the four foot side (or both rails have had a lot of wear).

The chairs could be at  90 deg. but that does not have to mean that the rail has to be! If the rail is going to be forged and machined to form the meeting point of the vee and to produce the form of the rail that fits in the bolt chair that supports the nose of the vee. Looking at the photo more closely it would appear that the wing rails are not parallel to the running rails for their full length. As we tend to model them.

 

As a follow on to the above, we do tend to look at drawings of the chairs but then forget about the rail that fits into them. So to really understand the crossing nose it would help to see the works drawings for them, the same could also be said about the switch rails.

 

In answer to your question in para. three. Yes I have built point work using plastic chairs in both 4mm (but not in P4) and 7mm (in both 7OF and S7), that was why I knew about the wing rails having to be bent downwards that you missed or misread, It could also be why I understood about some track gauges holding the rail vertical as well. I did make a type of roller gauge that helped to stop this all it was is a type that only had the track gauge turned without the rims that hold the outer parts of the railhead, too use it you have a normal roller gauge about five or six chairs in front of this type and glue the chairs below it in place.

 

Para. four, yes I do think that it looks better. 

 

OzzyO.     

[martin_wynne]

So to really understand the crossing nose it would help to see the works drawings for them, the same could also be said about the switch rails.

 

The drawings show that the rails forming the vee nose are vertical where they are spliced together. There is a twist in each rail, between the B and C chairs on shorter angles or C and D chairs on longer angles, so that the remaining length of the vee rail to the far end is inclined at the normal 1:20. It is a tricky twist to make, because the gauge face of the rail has to remain in a straight line. The foot of the rail is twisted outwards while holding the head straight. You can see the twist in the vee rails if you go looking for it, but otherwise it generally goes unnoticed.

 

The wing rails are inclined inwards at 1:20. The knuckle bend in the wing rail is not a sharp bend, but radiused so that it can be twisted at the same time to keep the rail top level. The wear pattern on this nearly new crossing shows the twist in the knuckle bend:

 

 

Notice also that the top of the vee nose is taken down below the level of the wing rails to allow for the coning angle on the wheels as they run off the wing rails on to the nose. Most crossings in photographs are well-worn, making these details difficult to see. So this picture of a nearly new crossing is especially helpful. Thanks to Mick Nicholson for the pic.

 

regards,

 

Martin.

[ozzyo]

The drawings show that the rails forming the vee nose are vertical where they are spliced together. There is a twist in each rail, between the B and C chairs on shorter angles or C and D chairs on longer angles, so that the remaining length of the vee rail to the far end is inclined at the normal 1:20. It is a tricky twist to make, because the gauge face of the rail has to remain in a straight line. The foot of the rail is twisted outwards while holding the head straight. You can see the twist in the vee rails if you go looking for it, but otherwise it generally goes unnoticed.

 

The wing rails are inclined inwards at 1:20. The knuckle bend in the wing rail is not a sharp bend, but radiused so that it can be twisted at the same time to keep the rail top level. The wear pattern on this nearly new crossing shows the twist in the knuckle bend:

 

 

Notice also that the top of the vee nose is taken down below the level of the wing rails to allow for the coning angle on the wheels as they run off the wing rails on to the nose. Most crossings in photographs are well-worn, making these details difficult to see. So this picture of a nearly new crossing is especially helpful. Thanks to Mick Nicholson for the pic.

 

regards,

 

Martin.

 

 

Hello Martin,

 

a very nice photo of a just about new crossing nose, one thing that it does show is the wear pattern on the new rails. This shows up that one rail has a different bend in it to the other.

 

You have mentioned a drawing for the rails that form the crossing nose, but you have not let any one see it so how can any one say if you are correct or not. In the photo that I posted from the first post and then saying that the twist had to happen within  the distance of the wing rails is a lot for any forger. Then the rail has to be machined to the correct shape for them to fit together.  

 

In your own photo the top bulge of the railhead is still showing and on the other side it will be about the same. How does that happen? IIRC the rail head will always be thicker than the rail web.

 

Yes I did also know that the front of the crossing nose is about  3/8"  lower than the running rails.

 

OzzyO. 

 

PS. I've just had a better look at the bigger photo of that crossing nose, that's a bit out!  I thought that you had put on the yellow lines, not that they were yellow chalk lines. For slow running it's not that bad, but bad enough.

[martin_wynne]

Hello Martin,

 

a very nice photo of a just about new crossing nose, one thing that it does show is the wear pattern on the new rails. This shows up that one rail has a different bend in it to the other.

 

You have mentioned a drawing for the rails that form the crossing nose, but you have not let any one see it so how can any one say if you are correct or not. In the photo that I posted from the first post and then saying that the twist had to happen within  the distance of the wing rails is a lot for any forger. Then the rail has to be machined to the correct shape for them to fit together.  

 

In your own photo the top bulge of the railhead is still showing and on the other side it will be about the same. How does that happen? IIRC the rail head will always be thicker than the rail web.

 

Yes I did also know that the front of the crossing nose is about  3/8"  lower than the running rails.

 

OzzyO. 

 

PS. I've just had a better look at the bigger photo of that crossing nose, that's a bit out!  I thought that you had put on the yellow lines, not that they were yellow chalk lines. For slow running it's not that bad, but bad enough.

 

Hi OzzyO,

 

I'm sorry, but you have lost me. I did add the yellow lines on the photo, to illustrate in another topic that the vee nose is taken down below the level of the wing rails. That's well worth replicating in a model to improve running quality through the crossing.

 

I don't understand your point about the two bends being different?

 

I'm sorry that I can't provide any drawings, my old SCSI scanner is out of action at present. If you have a copy of the PWI handbook "British Railway Track", in the 3rd Edition (1964) on p.102 and 103 are drawings for a bullhead vee nose and the "A" chair supporting it, showing that the rails are vertical where they are spliced together.

 

Similar drawings for inclined BS-113A flat-bottom track are on p.110, and this note on p.111 says:

 

"The wing rails are canted towards each other at the usual inclination of 1-in-20, and the point and splice rails are vertical from the nose of the crossing to the heel of the foot planing, beyond which they are twisted to the full inclination of 1 in 20, towards the wing rails. The twist takes place between two consecutive baseplates and the position of the twist for each crossing is shewn in Table 14 on p.113."

 

The table shows the twist between B and C for crossings below 1:6, between C and D for crossings 1:6 to 1:9, between  D and E for crossings 1:9.5 to 1:13, and so on.

 

The same information is repeated in the 4th Edition starting on p.117.   

 

Reference to a forger seems unhelpful on RMweb and I'm not clear what you are suggesting.

 

regards,

 

Martin.

[ozzyo]

Hello Martin all,

 

one of the problems with proof reading when the wife is talking to you!

 

When I mentioned the bend in the wing rail being different I had missed out one word 'slightly', when you look at the wear pattern on the rail to the right of the photo it is slightly different to the other one.

 

I had a walk down to my loco P/W yard this morning before I started on the puter to see if they had any crossings in stock, they had one but it was so over grown I could not get a decent photo of it. But I did have a nice chat to the supervisor about crossings and point work. 

 

The first was about F/B point work, it appears that there are two types vertical and inclined. With the inclined being used for higher speeds. What I was told about the vertical type is that the whole of the rail through the point is vertical and that adapter rails (about 3 or 4 yards long) are used to form the transition from the normal 1;20 incline to vertical. So six lengths of this rail per point and a number of Flat saddles under these rails, see below. You can just make out the V above the number.

 

Then we got talking about bullhead point work. What he said was all of the track work through a bullhead point was inclined. I asked about the crossing nose and he said that this was inclined as well. He may have meant that the railhead was inclined, I did not get chance to ask.

 

For forger read forge worker.

 

But for what we are working in a small twist in the rail would do to bring back the 1;20 incline, be it right or wrong. After all most people don't make the splice rail correctly with the inset for the spliced rail to sit into (or do they?).

 

OzzyO.