Anyone know what the purpose of..........

[DoubleDiamond]

........the raised plastic bit each side of a points 'V'?

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The reason I'm asking is, I laid a half circle of track (DC), in 2nd radius with a tunnel portal each end of the curve.

Tested the curve with the longest loco I've got and a couple of others, everything fine so far. Ballasted the track leading into the tunnels and sorted the portals............then it all went wrong..

Two Bachmann class 37's (Minimum 2nd Radius.......what can go wrong!), that I stupidly didn't test, kept stopping on the curve inside the tunnel.

Being new to all this, it took me quite a while to figure out what was going on. It turned out the wheels were jamming against the sides of the bottom of the cab. So much for 'Minimum 2nd Radius' then, yeah right!

What's all this got to do with points, I hear you ask

Well, I couldn't see any way 'round' it so, I decided to introduce a 3rd radius curve as well, to accommodate larger loco's that have a tantrum on 2nd radius track. Of course, this would mean cutting out track and fitting a right hand curved point (brand new), on the left and adding another tunnel portal to the right.

Still with me? Good, good.

Access was very limited and it was all a bit of a struggle, but got there in the end.

The class 37's went round the 3rd radius fine, no problem, whoohoo!............. " Hey, Mr Bachmann Class 40, come and have a go at this!"............ then the, "I'M gonna SMASH the lot with a sledgehammer" thought overwhelmed me You fix one problem, then create another.

The little wobbly wheels on the class 40 at each end (as on steam trains, 'Pony Truck is it'?), did a hop, skip & jump every time it went over the curved points and derailed. On closer inspection, It certainly looked like the leading wheels were jumping up on that raised bit of plastic each side of the 'V', even at the slowest speeds.

Deep breath, have a ciggie, relax and try to solve it.

"Where's the Dremel! .......little raised plastic thing, your gone mate!" I also went at the plastic 'V' itself with a Stanley knife. Sliced a bit off the top at an angle to look like a tiny ramp, so as to lessen the impact of the leading wheels hitting it.

The class 40 now sails through the curved points with ease.

So, what exactly is the 'point' of it?

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[DoubleDiamond]

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[Walkingthedog]

They are check rails. They guide the wheels when crossing the frog, the V bit. The reason the CL40 wheels raised up on them is probably because the back to back distance between the wheels is too large or too small. Should be 14.5mm. You should have checked that before attacking the points. You will probably find that some locos will now climb up onto the frog and derail because the check rail isn’t there.

One of my steam locos front wheels used to climb onto the frog so I added a thin layer of plastic to the inside of the check rail to pull the wheels away from the frog.

I fear you may regret what you have done eventually.

[DoubleDiamond]

Hi WTD.

Sorry, forgot to mention I'd already checked the back-to-back's on everything when the 2nd radius problem started. All seemed to be within limits.

What I'm trying to get at is, and this applies to all points I suppose, why is that particular bit raised?

Check rail, I get that. But why not make it the same depth for the wheels as the rest of the track?

As you are well aware, real track has the same wheel depth on points:

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There's probably a good reason for it but, I just don't understand why putting a raised obstacle in the way of the smooth running of any wheels on any loco can be beneficial to the layout.

Also, surely it can't be good for the actual train. Constantly hitting this raised bit on any points would, it seems to me, eventually cause damage to the train.

Maybe I'm just being thick as usual

[Brian]

Wheels flanges not the wheels are the things that are causing the issue here. They would on first thought possibly be be too deep and cause the wheel to lift off the rail or frog.
I can only think the plastic is there to aid support at the frog?
Making it fractionally deeper shouldn't hurt, so long as you don't go too deep.
Many modellers will replace older locos wheel sets to reduce flange depth (and wheel width too).

[Brian]

Wheels flanges not the wheels are the things that are causing the issue here. They would on first thought possibly be be too deep and cause the wheel to lift off the rail or frog.
I can only think the plastic is there to aid support at the frog?
Making it fractionally deeper shouldn't hurt, so long as you don't go too deep.
Many modellers will replace older locos wheel sets to reduce flange depth (and wheel width too).

The part I have assumed you're mentioning is where I have marked it in red.

[Mountain Goat]

I believe (If my memory serves me correctly as about a year ago I looked it up as I was making my own points) that they are called wing rails. They are designed to guide the wheels through the frog part of the point. Yes, a simple point can be made without them, but other locos and rolling stock may suffer. I do have some thoughts. Are the front wheels set too high so they bounce. I used to find myself opening out the gaps slightly on the checkrails on the other side (Which ae plasticnon your points). It could be that the wheel flanges on the loco are deeper then the point will cope with. I did deepen mine a little but go easy. (Alternatively wheels with shallower flanges may help). Lima locos had deep flanges which can be an advantage in holding the rails at speed, but points need to cope with them by having sifficient depth. I was running deeper still flanges made by early Triang locos on my points so I slightly deepened and widened the flangeways and all my locos, both new and old were able to run ok over them.
(Brian just posted before I wrote this... I mwan I had already written this but posted after Brian posted his post).
I used a broken piece of hack saw blade to deepen my flangeways through the frog. Go easy if doing it.

[DoubleDiamond]

Ah, right, wheel flange.........thanks Brian.

Yes, that's the exact bit of raised plastic I'm on about.

"Fractionally deeper".........well, maybe I did go a bit overboard when drilling it out, but that was only because it's in an awkward position, in the tunnel, and screwed down & ballasted.

Would have been better on the bench with mini files obviously. Anyway all trains seem to be coping with the 'fix'............for now

[DoubleDiamond]

'Wing rails eh'........thanks MG. I'm learning all kinds today

"Are the front wheels set too high so they bounce"........I wouldn't know how to check that. But, if it helps, the same thing was happening to other loco's, mainly steam with the small 'pony truck'? wheels at the front. Looking very closely, when they pass over any point, the bump/jump is very noticeable.

Which begs the question, why don't Hornby, Peco, Bachmann etc, make the wing rails slightly deeper so as to accommodate the wheel flanges......... on newer trains at least. The two just aren't compatible. Maybe the Chinese flanges aren't as deep

Well, this should help :

https://www.railjournal.com/images/TTCI-fig-1.jpg

[Walkingthedog]

Sorry I thought you were referring to the check rails. Is your hill removable?


How old is the CL40?