Bachmann Collet Goods tender derailing

Discuss model railway topics and news that do not fit into other sections.
abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: Bachmann Collet Goods tender derailing

Postby abenn » Tue Nov 06, 2012 8:01 pm

Thanks beeman, that explains it. But reducing the back-to-back dimension is likely to result in other problems such as, dropping off the rail on curves as you say, or fouling the check rails, isn't it?

Bigmet, the tender can't go over the "inner" branch of any of my three curved points without derailing, when pushed by hand. Coming from the branch direction, the derailment occurs just after the first pair of wheels passes off the points onto the 3rd-radius "main line" curve that's connected to them. The centre pair of wheels is still on the point blade, and it's the leading pair, going onto the curve, that derails.

Some of my 0-6-0 locos have flangeless centre wheels. What are the pitfalls, if any, of carefully grinding off the flanges? Are the flangeless wheels slightly smaller diameter than their neighbours, or perhaps bevelled slightly, so they won't cause a problem if they drop off the rails on a tight curve?

Bigmet
Posts: 7647
Joined: Tue Aug 14, 2007 2:19 pm

Re: Bachmann Collet Goods tender derailing

Postby Bigmet » Wed Nov 07, 2012 10:09 am

Next step: before you modify the wheels, simply remove the centre wheelset and check that the tender is definitely OK as a four wheeler through the trouble spots; first on its own, then attached to the loco. You don't want to bother modifying the wheelset if it won't produce a cure; all you are doing by removing flanges is making it a four wheeled vehicle so this action is fully testable in advance.

Second, what size and style of wheel are you looking for: tyre diameter, number of spokes or disc, diameter of axle ends, length over axle ends? You never know someone here might have a suitable flangeless wheelset lurking. Typically the flangeless wheel tyre should be just above the rail, avoids it catching on the rail side as it comes off a sharp curve and recentres over the rail.

The wheelset construction is what will determine how you go about modifying it. If it is a metal rim on a plastic moulding, and especially if the axle is plastic, taking the rim off the wheelset to modify it is usually best.

Personally I would persist with all flanged, looking at modifying the tender frames and wheelbosses as required for more sideplay, and if necessary going for alternative wheelsets. The loco has a longer wheelbase than the tender, all flanged, and it goes round these curves. There is no fundamental technical obstacle.

beeman
Posts: 269
Joined: Tue May 04, 2010 12:21 pm
Location: Within earshot of the sea and the Paignton&Dartmouth

Re: Bachmann Collet Goods tender derailing

Postby beeman » Wed Nov 07, 2012 10:59 am

I agree fully with Bigmets suggestions. There is obviously a 'tolerance' between wheels 'B to B' and track to allow some sideways 'float', as said if you remove the center axle try it as a 4 wheel tender, then check the axle/wheelset around the problem area for 'tolerance' to check if it is prudent to narrow. don't forget we are only talking decimal points of a MM. but which can make all the difference. Your abilities seem logical/capable when you suggest removing flanges and a beveled edge to the tyre. Good Luck Beeman.
You wo'nt find you 'CAN' unless you 'TRY'.

abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: Bachmann Collet Goods tender derailing

Postby abenn » Wed Nov 07, 2012 7:47 pm

Thanks Bigmet and beeman. Tomorrow I'll try it as a 4-wheeler and, while the centre wheels are off, I'll look closely to see if/how I can reduce their back-to-back a smidgin.

abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: Bachmann Collet Goods tender derailing

Postby abenn » Thu Nov 08, 2012 7:58 pm

Success, I think :)

The tender ran over the points okay with the centre wheels removed. Then, while I had the axle off I could see what you were saying, beeman. I pulled one wheel off the plastic joiner, filed a bit off the end of the joiner and reattached the wheel, resulting in a narrower back-to-back measurement. After a couple of tries, with a bit more filed off each time, I got it to run okay without derailing. I reduced the back-to-back on one other pair of wheels too for good measure.

Thank you.

beeman
Posts: 269
Joined: Tue May 04, 2010 12:21 pm
Location: Within earshot of the sea and the Paignton&Dartmouth

Re: Bachmann Collet Goods tender derailing

Postby beeman » Fri Nov 09, 2012 10:19 am

Glad to have been able to help and thanks for showing your appreciation by replying to say thanks. Too many reading these Forums can't be bothered to do just that, even when successfully carrying out advice. I feel sure this is one reason many of the more capable/experienced , albeit still readers, don't bother to respond to queries.Pleased to hear you have solved your prob. Cheers. Beeman
You wo'nt find you 'CAN' unless you 'TRY'.

Bigmet
Posts: 7647
Joined: Tue Aug 14, 2007 2:19 pm

Re: Bachmann Collet Goods tender derailing

Postby Bigmet » Fri Nov 09, 2012 10:35 am

Likewise it is always useful to hear what has finally cracked it.

Want to start on the road to being an engineer? Then make a note somewhere (I systematically use the service sheet for the loco, or just one sheet plus attachments if required, if operating a class of the same type) of what you have done and why. There's nothing like 'banking' the knowledge for future reference.

abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: Bachmann Collet Goods tender derailing

Postby abenn » Fri Nov 09, 2012 8:22 pm

I have a piece of paper somewhere that says I am an engineer :mrgreen:

I do keep a spreadsheet of repairs and mods I make to my RC helicopters (my other hobby), so maybe I should do the same for my railway.


Return to “General Model Railway Discussion / News”

Who is online

Users browsing this forum: No registered users and 9 guests