Point problems

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Andrew
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Point problems

Post by Andrew » Wed Jun 19, 2019 6:20 pm

Hello all,

I seem to have a problem with the points I've recently laid. Some of my wagons just don't like them. In particular my two WHR coal wagons, scratch built on Binnie wheels always want to take the right hand track, regardless of which way the points are set.

I thought it might be a back-to-back issue (these two wagons were a little under-gauge), but sorting tat out doesn't seem to have solved the issue.

I'd previously tested the points with other wagons and all seemed well, so this is rather disappointing, any ideas would be most welcome!

Thanks,

Andrew.

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philipy
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Re: Point problems

Post by philipy » Wed Jun 19, 2019 6:35 pm

First few thoughts (apologies if I'm trying to teach granny..!),
1) if you push it across a flat table ( not on rails), does it tend to curve off to one side?
2) are the axles dead parallel, are they at right angles to the chassis and are the wheels equal distances from the solebars?
3) does the chassis sit perfectly on flat surface?

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Andrew
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Re: Point problems

Post by Andrew » Wed Jun 19, 2019 6:38 pm

philipy wrote:
Wed Jun 19, 2019 6:35 pm
First few thoughts (apologies if I'm trying to teach granny..!),
1) if you push it across a flat table ( not on rails), does it tend to curve off to one side?
2) are the axles dead parallel, are they at right angles to the chassis and are the wheels equal distances from the solebars?
3) does the chassis sit perfectly on flat surface?
I fear the answer to at least one of those questions is "no", I'm not much good at precision... Neither's granny...

I'll test 'em and see what I can find out... Thanks for the pointers, I'll let you know!

Andrew

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Andrew
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Re: Point problems

Post by Andrew » Wed Jun 19, 2019 7:28 pm

Hmmm... It's not good!

1) Yep
2) I've seen worse (on my own stock,I hasten to add!), but no...
3) Yes! There had to be some good news somewhere!

I think I'm going to have to rebuild the underframes, but that won't be easy because the axleguards are Araldited to the solebars, and the solebars are stuck to the floor with "stronger than the wood itself" wood glue. Oh, and the brake gear's stuck to all of that! Oh dear...

I've reminded myself why much of my stock uses Big Big Train running gear!

Thanks,

Andrew.

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Peter Butler
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Re: Point problems

Post by Peter Butler » Wed Jun 19, 2019 8:21 pm

It's hard to stress the importance of a perfectly built chassis to ensure good running. I spend absolutely minutes on building perfect chassis.....
IMG_1936.JPG

OK, so the chassis isn't the sort of thing you need, but you will notice the use of metal wheels and plenty of low-down weight, which should all add up to better running.
The best things in life are free.... so why am I doing this?

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tom_tom_go
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Re: Point problems

Post by tom_tom_go » Wed Jun 19, 2019 8:40 pm

What points are you using Andrew, is it the newer short radius Peco SM32 type?

Some of my first built rolling stock items ride up on the frog which is down to back to back measurement being incorrect, however, on the original longer radius points they are fine.

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Andrew
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Re: Point problems

Post by Andrew » Wed Jun 19, 2019 9:40 pm

Hi Tom,

No, it's Peco, but not the small radius ones. Oddly, although they've not been used much, I've not noticed the wagons struggling elsewhere, it's since I've laid the new points at the top end of Penlan's loop. The trackwork there's not brilliant, I'll level it all properly when I ballast, but I've done a temporary tamping job so I don't think it's an alignment or levels issue... Perhaps I'll test the wagons a little more thoroughly on other pointwork tomorrow evening, it's possible I've not used them enough to spot particular problem areas...

Cheers,

Andrew.

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Re: Point problems

Post by Andrew » Thu Jun 20, 2019 5:38 pm

Result!!!

Testing on some other, more accessible, points meant I was able to observe what was going on more closely - the flanges were riding up over the point blade. Googling the symptom (never usually a good idea!) made me re-visit the back-to-back, and I found that I'd still not quite got that right. Fortunately I was just able to get the axles out without dismantling everything, and I was able to shave enough off the centre of each wheel to push them out to the proper 28mm. At the same time I was careful to ensure wheels were equidistant from the solebar (thanks Philip!) and now they run through the points quite happily - hooray!

Careful and accurate assembly of running gear has always been my Achilles (w)Heel - I feel lucky to have got away with it this time and will endeavour to follow the advice received here in future builds, thank you!

All the best,

Andrew.

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Re: Point problems

Post by GTB » Fri Jun 21, 2019 3:55 am

Andrew wrote:
Thu Jun 20, 2019 5:38 pm
Testing on some other, more accessible, points meant I was able to observe what was going on more closely - the flanges were riding up over the point blade.
Good troubleshooting. Now you know, so it won't bite you again.

I had wondered if that might be what was going on. I used Binnie curly spoke wheels on my timber bogies and found they have thinner flanges than the G1 coarse wheel standard and the radius on the back of the flange is fairly sharp.

The wheel check gauge is more important than the back to back measurement, contrary to popular belief. i.e. it is the distance from the front of one flange to the back of the other that determines what happens through a turnout.

Thin flanges need a wider back to back measurement to maintain the wheel check gauge, which is why I had to set the wheels on my timber bogies to 40.5mm b to b rather than the 40mm I use for the wheels I make.

This is just an observation, not a criticism........

From hard won experience, I fit running gear in place with screws, so it can be partially dismantled and the wheels removed for maintenance/modification/replacement in the future. It's also easier to slot a screw hole than break a glued joint if something moves, or is in the wrong place.

I'd be in real trouble now if I hadn't, as I plan to modify the wheel sets on the 4 wheel wagons to fit a free running wheel on each axle.

Regards,
Graeme

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Re: Point problems

Post by Oily Rag » Fri Jun 21, 2019 9:34 am

That is excellent advice Graeme. I still have a problem as many will know but have a solution to be implemented. However, I also learned the hard way concerning what I call "serviceability", i.e the ability to dismantle everything to make changes or repairs later. I still have my fixed cylinder De Winton to rebuild because of this very problem in putting axle box bearings through holes instead of slots. Its going to be a pain to strip.
Wherever I can I now use slots in frames and make my bearings from square brass (5/8" or 16MM) turned and bored in a self centering 4 jaw and have a little home made jig for drilling tapping size for M2. That way wheelsets and drive trains can be dropped at will and there is some flexibility to set up the chassis.
Regards
Ian
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