Grinding off wheel flanges

[Throppers]

Has anyone any experience of grinding off wheel flanges? I have an OO gauge Bachmann class 37 which de-rails on points as the radius is too tight (oddly my other identical loco manages them but the problem loco bogeys don’t turn as much). I am thinking of grinding off the flanges of the middle wheels on each bogey to help it negotiate the tight curve. Any thoughts?

[The Bigbee Line]

Years ago I removed the traction tyres from a Lima Class 73, the razor flanges gained even more height.  I took a file to the lima wheels, finishing off with the wheels motoring and a light touch to finish.  The trick was to file down to a fence of some kind, I just used a handy piece of steel strip.  Complete crude butchery, but it worked.

 

Take a file, and take a chance

Edited October 25, 2018 by The Bigbee Line

[Dunsignalling]

Sounds more like the problem loco just doesn't have enough rotation in the bogies if the other one takes the curve OK. I'm guessing the curve must be very tight as Bachmann diesels don't usually bat an eyelid at anything down to setrack radii.

 

If the wheels on both are similar, altering those on one isn't going to make any difference - the bogie wheelbase is only a fraction of the bogie centre spacing, after all.

 

Another thing to look for is how much the locos can rock sideways on the bogies - if the troublesome one is significantly more restrictive in that sense, a tight curve can cause one side to lift and lose contact with the rail.

 

If the curve is laid to a very tight radius (sub-18") with flexible track, it's most likely got a tight spot - that's difficult to avoid and sectional track is usually a more reliable choice when the radius gets down to the dimensions available.

 

It's important to get clear about what's the same between the two locos and what's different - the latter will almost certainly prove to be the root of the problem if the track isn't.

 

John

Edited October 25, 2018 by Dunsignalling

[sharris]

As the two engines are identical I'd investigate why the bogies don't turn so much before attacking the wheels.

[Penrhos1920]

Check that the middle axle on each bogie isn't lower than the outer axles. It's a common problem

[cravensdmufan]

Has anyone any experience of grinding off wheel flanges? I have an OO gauge Bachmann class 37 which de-rails on points as the radius is too tight (oddly my other identical loco manages them but the problem loco bogeys don’t turn as much). I am thinking of grinding off the flanges of the middle wheels on each bogey to help it negotiate the tight curve. Any thoughts?

Before you go filing down the flanges on the centre wheels, have you checked that the middle axle isn't set too low?  It is sometimes still a problem with Bachmann Co-Co bogies on both 37's and 47's.

 

I purchased an NSE 47 just a year ago and it derailed on points, even second radius ones  The same old problem still exists - to cure it see this post:

 

http://www.rmweb.co.uk/community/index.php?/topic/13947-Bachmann-class-47/page-17&do=findComment&comment=1063123

 

I usually place my locos on a piece of glass - you will soon see if the outer wheelsets sit higher than the middle ones.

 

Just a thought....

Edited October 25, 2018 by cravensdmufan

[Fat Controller]

Check the back-to-back measurements are the same on all axles

[adb968008]

If you do ultimately go down the filing flanges route, ive filed down flanges on old triang locos, which had really deep flanges using this mechanism...

 

Remove wheelset, remove one wheel off the axle.

Put the axle with 1 wheel into your drill chuck & tighten

Set the drill in a vice, turn it on and let it spin, checking its even rotation..

Apply a file to the flange to get an even flange.

Check periodically how much is removed, it can go down faster or slower than you think depending on drill speedand file pressure applied.

Remove the wheel, fit the other wheel & repeat.

 

I used a standard expo drill, no sparks just filings, if you press to hard it ceases to rotate, to lite.. expect it to take ages... 20 mins plus, but you get to be certain how much you take down.

Old fashioned but works, today you could replace the wheel easy enough.

Edited October 25, 2018 by adb968008

[SRman]

Some of those old Triang wheels were very hard. I have a set of wheels from the old Southern Electric (R156) which a friend turned down for me somewhat crudely. In the process of doing that over a period of nearly two months, he blunted his lathe tools, blunted his TAFE (college) lathe tools, and blunted his lecturer's tungsten-carbide lathe tools!

Being into historic toys and models, my friend did some research, and found that at some stage, Triang got hold of some war surplus armour plate and had melted it into the wheel mix.

[Throppers]

Thanks all for replies so far. 

 

To answer a couple of questions raised...

The back-to-back has been checked with a proper gauging tool and is fine.

The points I'm using are standard Hornby and Peco. Changing them is sadly not really an option as it would mean almost totally re-doing my layout.

The problem of the centre axle being low was mentioned... I have checked this on a flat surface and all 3 axles are level (oddly my other B'mann 37 which doesn't derail does have a slightly dropped middle axle!).

 

I will avoid grinding the wheel for now based on advise and see about getting more rotation out of the bogey. 

[34theletterbetweenB&D]

On your loco with restricted bogie swing there are several simple potential causes.

 

Check that the cosmetic outer bogie frames are fully 'home' where they clip onto the gear towers.

Check for bufferbeam detail fouling the bogie, bogie mounted couplers in particular.

Check for 'tethering' by the connecting wires to the pick ups snagging on the fixed structure.

 

As already suggested, careful comparison to the mechanism that has sufficient bogie swing should provide useful guidance.

[Throppers]

So I've done some further checking today. There appears to be enough bogey swing as when running over the points, the bogey doesn't need to swing to it's full potential. However, the mechanism of the derailing is the front outside wheel (front left if going over a right turnout and front right when going through a left turnout) jumps off the rail at the gap before the frog, causing it to jump over the frog.

 

The wheel spacing is correct as my back to back tool is a snug fit between the wheels on all the axles however I'm wondering what modification I can make to allow the wheels to pass through the points. 

 

The below pics show the loco on approach to the frog and then having jumped off through the gap in the points just before the frog from top and side...

 

 

[sharris]

I don't know what Bachmann do with their bogies, but some things I wonder... 

 

1. Is there anything dragging in the bogie (e.g. some sort of spring mechanism, or maybe even just springiness of tight wiring) that is trying to return the bogie to centre and pulling the front wheel off the track in the crossing gap? 

 

2. Is the bogie level front to back - do all wheels sit evenly on the track or is it somehow 'back heavy' and the front wheels are raised a fraction? 

 

3. Do both bogies have the same problem, or is it just one end? 

 

4. Is there sideplay designed into the bogies (can some of the wheels move from side to side) so that they can cope with the tight radii - is anything jamming the sideplay?

 

Is it just an accident of tolerances that one loco works on set-track points and the other doesn't? 

[The Johnster]

Check that the bogie has up and down play about it's axis as well being able to swing freely, and that this play is available thoughout the swing.  Compare this directly with the identical loco that runs well through the same turnouts to establish what degree of play is necessary.

[PMP]

From your description it’s very likely to be a back to back problem if it’s only this axle causing the problem, or a slight binding in the bogie rotation, check wiring runs as others have mentioned and the chassis for any mould lines etc that may restrict the bogie swing. Grinding the centre wheel will not make a difference.

Does this only happen on one point, or all of the same type?

My first easy ‘fix’ would be make sure the pickups aren’t providing extra outward force to the left hand side. Try swapping the axles on the bogie leading axle for the rear, and between bogies. Ensure the b2b is consistent on all axles on the bogie. As they’re not handed you can also rotate them through 180 degrees. If the wiring and build quality are all good it again points to the wheelsets, and adjust back to backs to suit. ( I know you’ve checked them, but sometimes just a fraction of a millimetre either way will make the difference. Failing that, replace the point, or the locomotive)

Edited October 26, 2018 by PMP

[E3109]

If you do ultimately go down the filing flanges route, ive filed down flanges on old triang locos, which had really deep flanges using this mechanism...

Remove wheelset, remove one wheel off the axle.

Put the axle with 1 wheel into your drill chuck & tighten

Set the drill in a vice, turn it on and let it spin, checking its even rotation..

Apply a file to the flange to get an even flange.

Check periodically how much is removed, it can go down faster or slower than you think depending on drill speedand file pressure applied.

Remove the wheel, fit the other wheel & repeat.

I used a standard expo drill, no sparks just filings, if you press to hard it ceases to rotate, to lite.. expect it to take ages... 20 mins plus, but you get to be certain how much you take down.

Old fashioned but works, today you could replace the wheel easy enough.

Did that recently with a Tri-any EM2, the plastic wheels were easy enough to do, due to their design I simply gripped them in the drill chuck by the stub axle (be careful not to over tighten them) and, as you suggest ADB clamp the drill to a table or similar, this forms an impromptu lathe and then simply turn the flanges down with a file.

It's also worthwhile coning the treads, as the Tri-ang wheelsets have flat treads for some reason.

 

The two powered wheelsets were more tricky in that they wouldn't fit in my standard 1/2" chuck. Improvisation again is the key here, ended up holding the axle between my thumb and forefinger and with spit as lubrication (!) used my Dremel type drill, with a stone wheel fitted, at an angle to the flanges which causes the wheelset to rotate while carefully grinding the flange down.

 

Sounds a bit 'belt and braces' and it is, but it does work.

The only thing you need to be aware of is that the wheels appear to be sintered rather than turned, so take extra care while grinding. I managed to knock a bit of flange off, as I assumed these wheels were turned but think I got away with it, by grinding the remainder down to match.

The back to backs still aren't right on the metal wheels and I was only able to apply minimal coning without risking damage, but they appear to pass through Code 75 turnouts well enough.

Need to have a proper running session before deciding whether they need further work. Obviously the plastic wheels were much easier to modify than the metal ones.

Edited October 26, 2018 by E3109

[SRman]

Something to bear in mind if turning the flanges down a bit; they do not have to be entirely concentric, since the locos (or rolling stock) do not normally actually run on the flanges. I filed down some Lima wheel flanges using a similar method to that E3109 described, but there were a few slight dips in the end result. This didn't affect the running in any way.

Going back to the class 37 problem, there might be a case for actually reducing the back-to-back measurement very slightly for the leading axles on each bogie and testing with that setting.

[sharris]

Going back to the class 37 problem, there might be a case for actually reducing the back-to-back measurement very slightly for the leading axles on each bogie and testing with that setting.

It would also be worth placing the loco straddling the point and starting it up to see if the innermost wheels on the bogies have the same problem.

[davknigh]

You might want to check the points themselves as they can sometimes be tight to gauge. Beyond that check the sideplay on the axles to make sure that it is equal on each side.

 

HTH

 

David

[Il Grifone]

It's possibly a problem that Bachmann wheels are made to NMRA standards, whereas Peco track is made to their own*. Check the check gauge (B-B + flange thickness / rail to inside edge of the check rail), because if their is a problem here derailment is assured. Check gauge is critical not the back to back. though I find 14.5mm is usually a good compromise. The tolerance needs to be tighter than a fraction of a millimetre - +/- 0.1 mm is not too generous. Is the B-B gauge actually correct? I set mine with a vernier caliper. From the photos the wheel seem a fraction too far apart, but that could be the angle of the shot. can you try the effect of removing the centre axle altogether? (I have no experience of the Bachmann model - my 37s are all Tri-ang!)

 

Originally Peco Streamline track was designed to accept wheels from Tri-ang (60s less coarse type) to 'scale'. It has been tightened since, but the flangeways are still on the generous side. I have one Peco point on which one particular freight car always derailed. It was a Bachmann gondola IIRC, but a wheel change solved the problem.

[uax6]

Another way round it is to pack out the check rail, so making it tighter against the stock rail. A sliver of plasticard in the gap will help to push the flange on that side back towards the stock rail and keep things on track. 

 

Andy G

[jamesg]

I recall a similar problem with a long wheelbase van derailing on Hornby points.  Adding thickness to the outside of the check rail with a thin strip of plastic card, fixed with Uhu glue, forced the flange to contact the check rail (something that's not supposed to happen on the real thing).  Also easy to roll back the change if it doesn't work.

 

Andy G's beaten me to it!

[34theletterbetweenB&D]

...Is it just an accident of tolerances that one loco works on set-track points and the other doesn't? 

 That's the right style of question. But leave 'tolerances' out of it as that implies an integrated design approach for the mechanism and track combination.

 

Now that I can see that the point is a set track item (designed in the 1950s for HO and later arrived in OO in a desperate catch up attempt by Triang Hornby) while the mechanism is (as others have observed) probably conforming to NMRA RP's, the only significant design element that has commonality is the gauge.

 

Just look at the flange gap, vs. the flange thickness. Probably tightening the back to back will help. But that may degrade performance on other designs of track.

[Throppers]

Thanks for the tips so far. I have loosened the bogey retaining screw but it doesn’t seemed to have achieved much. There have been a few mentions of check rail and stock rail. Which rails are these? Thanks.

[The Johnster]

It's possibly a problem that Bachmann wheels are made to NMRA standards, whereas Peco track is made to their own*. Check the check gauge (B-B + flange thickness / rail to inside edge of the check rail), because if their is a problem here derailment is assured. Check gauge is critical not the back to back. though I find 14.5mm is usually a good compromise. The tolerance needs to be tighter than a fraction of a millimetre - +/- 0.1 mm is not too generous. Is the B-B gauge actually correct? I set mine with a vernier caliper. From the photos the wheel seem a fraction too far apart, but that could be the angle of the shot. can you try the effect of removing the centre axle altogether? (I have no experience of the Bachmann model - my 37s are all Tri-ang!)

 

Originally Peco Streamline track was designed to accept wheels from Tri-ang (60s less coarse type) to 'scale'. It has been tightened since, but the flangeways are still on the generous side. I have one Peco point on which one particular freight car always derailed. It was a Bachmann gondola IIRC, but a wheel change solved the problem.

 

I picked up an original spec Triang 'shorty' clerestory, with early 60s wheels, last year and found that it would run quite happily through Peco and current Hornby pointwork despite riding the chairs a little with the flanges.  This coach has since had current Hornby coach wheels fitted and running is much better, but it shows how 'tolerant' even modern Peco track is.  Two more shorties recently acquired to a more recent Hornby Made in China spec fly through no problem!