Bachmann 93xx Pony Truck

[sjrixon]

At £5 I should strip mine for spares and buy a new loco Thanks for the heads up though, might be useful for someone.. 

[Il Grifone]

A few investigations, having located one of my Mainline 53xx (less motor, as the diecast frames have failed - the spigot the intermediate gear rotates on has broken off and a tender drive is planned). My calculations give a position of about 25mm behind the leading axle for the pivot. on the model ithis dimension is only about 20mm, which coupled with the excessive sideplay in the leading drive axle explains the tendency of the pony truck to derail. On the track and propelled by another locomotive, she lurches into the curves in just the manner that would be expected and needless suffering the odd derailment.

 

First I'll add some washers to reduce the driving axle play and then modify the pony truck to pivot further back. The front keeper plate screw looks like a suitable location for the new pivot.

 

I'll report back, when I get around to it. Other work in the rest of the house has seriously curtailed modelling time....

[Richard Mawer]

Hi

 

Mine is now running really nicely after having a tender drive attached and with the shims fitted between the driving wheels and the chassis. The reduced play keeps the pony under control.

 

 

So that's a Mainline body on a Bachmann chassis (motor and gears removed) with a Hornby tender!

 

I just need to blacken the shims.

 

Rich

[Richard Mawer]

A few investigations, having located one of my Mainline 53xx (less motor, as the diecast frames have failed - the spigot the intermediate gear rotates on has broken off and a tender drive is planned). My calculations give a position of about 25mm behind the leading axle for the pivot. on the model ithis dimension is only about 20mm, which coupled with the excessive sideplay in the leading drive axle explains the tendency of the pony truck to derail. On the track and propelled by another locomotive, she lurches into the curves in just the manner that would be expected and needless suffering the odd derailment.

 

First I'll add some washers to reduce the driving axle play and then modify the pony truck to pivot further back. The front keeper plate screw looks like a suitable location for the new pivot.

 

I'll report back, when I get around to it. Other work in the rest of the house has seriously curtailed modelling time....

David, how did you get on?

 

I thought I had sorted mine, but upon reflection and subsequent use, all I have done is made it loads better, but not good enough.

 

To take out enough play on the drivers, the loco had so much physical resistance that the loco would move because of the motorised tender but often the drivers wouldn't turn. It skidded along. So I took one of the shims out. I even tried two in and shaved down, but whatever combination I could either have no derailments but skidding, or occasional derailments and turning drivers.

 

I have now gone back to your note above and have made a plastic bracket that pivots the pony off the front keeperplate screw. I have not been able to test it yet though.

[Il Grifone]

David, how did you get on?

 

I thought I had sorted mine, but upon reflection and subsequent use, all I have done is made it loads better, but not good enough.

 

To take out enough play on the drivers, the loco had so much physical resistance that the loco would move because of the motorised tender but often the drivers wouldn't turn. It skidded along. So I took one of the shims out. I even tried two in and shaved down, but whatever combination I could either have no derailments but skidding, or occasional derailments and turning drivers.

 

I have now gone back to your note above and have made a plastic bracket that pivots the pony off the front keeperplate screw. I have not been able to test it yet though.

 

I'm afraid the project has stalled. I did check the pivot position of the prototype and it's well back from the Mainline position. (About a foot IIRC correctly - it was several months ago.) However, I remember there were one of two issues on test regarding derailments*, but, considering the jerk that occurs on entering a curve, not unexpected (They are sharp on my test track (about 1" radius greater than 1st radius - it's Trix fibre 'large' radius and the rail joints are not as smooth as they could be). It looks like I shall have to move the pivot point back and possibly add spring control. Whether I need to eliminate some side play remains to be seen.

 

* She stayed on the rails most of the time as long, as the speed was reasonable. (The prototype was good for 70 mph apparently.)

 

David

[DCB]

David, how did you get on?

 

I thought I had sorted mine, but upon reflection and subsequent use, all I have done is made it loads better, but not good enough.

 

To take out enough play on the drivers, the loco had so much physical resistance that the loco would move because of the motorised tender but often the drivers wouldn't turn. It skidded along. So I took one of the shims out. I even tried two in and shaved down, but whatever combination I could either have no derailments but skidding, or occasional derailments and turning drivers.

 

I have now gone back to your note above and have made a plastic bracket that pivots the pony off the front keeperplate screw. I have not been able to test it yet though.

 

If the Chassis is Bachmann not Mainline, You could take the wheels off the axles and and insert spacing washers between chassis and wheels instead of the shims.  Bachmann wheels have squared axles so you can easily get the quartering right again.   Don't try it with Mainline as they don't have squares and I can never get them to run again after having the wheels off.

 

You could shave down the shims so only a small area around the axle bears on the wheel hub.  It would be a lot of filing but might be worth it on a Mainline chassis where you daren't take the wheels off the axle.

[Richard Mawer]

If the Chassis is Bachmann not Mainline, You could take the wheels off the axles and and insert spacing washers between chassis and wheels instead of the shims.  Bachmann wheels have squared axles so you can easily get the quartering right again.   Don't try it with Mainline as they don't have squares and I can never get them to run again after having the wheels off.

 

You could shave down the shims so only a small area around the axle bears on the wheel hub.  It would be a lot of filing but might be worth it on a Mainline chassis where you daren't take the wheels off the axle.

 

Thanks. Its a Bachmann Chassis. I'll see how the new pivot goes before I pull the drivers off, but its good to know.

 

Rich

[Richard Mawer]

Hmmm

 

Well that hasn't worked either.

 

Even with two shims in (one each side) restricting side play on the drivers to the point of the ocassional skid, the blessed pony would not stay on the rails.

 

It works going anti-clockwise, but not clockwise.

 

Option A try and spring load it to the left.

 

Option B ditch it and buy something that does work.

 

I have already ditched one of them and bought a 72xx. So what else is there 1930's or earlier, not a 4-6-0 that would have hauled local/semi-fast passenger trains? I already have a Bulldog, Dukedog, 51xx and two Dean Goods.

[DCB]

Had a brand new Bachmann 53XX form the Cambrian Coast double presentation set running in last evening with no derailing issues on Peco Streamline code 100 with some 2ft radius points.    The brand new unused Manor's rear driving wheels fell off after an hour......

[Chimer]

Very low tech compared with fitting shims, etc., but fwiw, and with acknowledgement to whoever first suggested this in a different thread ......

 

I had a similar problem with the leading pony on a Hornby Fowler 2-6-4T.  I just took a bit of scrap grey card (about 2cm x 1 cm) from a Metcalfe kit, scored and folded it at the mid point, and pushed it fold first between the truck and the body.  The springiness seems to successfully eliminate the ability of the wheels to bounce or otherwise ride up over the rails.  I didn't even stick it in place and it's still there doing the job, happily surviving Peco small radius Code 100 crossovers and 3rd radius settrack curves.

 

Cheers

 

Chris

[Richard Mawer]

Stubby47, on 04 Jul 2017 - 09:07, said:

Silly idea time... can you add a piece of the metal you've used for the inclines under the offending slips and add a magnet to the pony truck ?

 

Now that's a new idea. There's a lot of merit in that.

 

This morning's appointment is a late one so I had a few minutes to spare and decided to trial one of the things I mentioned in my reply to Ray. Withe aid of a blob of blutac I fixed the pony dead ahead. She ran straight through the junctions both ways numerous times without any derailments. I tried with 1, 2 and no shims and all worked perfectly. I put her round the dumbell and wasn't sure if there was some pull on the blutac or not. They are 4th radius set track so I hope ok. The eight couples go round ok. I have yet to trial points in the loco yard. They are small radious peco. All the running line ones are medium or curved.

 

Fingers crossed but fixing not floating might, just might, be the answer. If it doesn't like being actually fixed I will have to try and severely limit the movement, perhaps with wire.

 

David, I wonder if Bachmann have improved the design? Is it still a split chassis model? Is there any springing or restriction on the pony?

 

Chris, that sounds more fruitful than my added lead. I'll bear that in mind.

[Richard Mawer]

UPDATE

 

Success - so far - well best yet.

 

Well first off, it didn't like the pony being fixed (0-8-0 effectively). Just couldn't take the curves even with reasonably large radius.

 

But working off Chris Chimer's idea I just simply added another piece of lead on top of the rest already fixed to the pony, but this time it filled the gap under the leading edge of the chassis. This prevents any upward movement and I presume adds some resistance to sideways movement but doesn't prevent it.

 

So far she runs satisfactorily in both directions on the continuous run section.