I bought a Bachman 4-8-4 at a very low price, but have some tight radius curves. I run 6 driver locos. The 4-8-4 derails too often.
Would it be smart to file off 2 driver flanges to make them “blind” (4-8-4 tracks like a 4-6-4)? If so, which drivers (front 2, rear 2, 2 in the middle)?
I suspect that may help, but it’s no panacea. Typically, blind drivers on the prototype are somewhat wider, although they may be wider anyway on a model. Then the mechanism has to hold them so they don’t drop below rail height on sharp curves. The Bachmann probably isn’t sprung, but may have enough play that the blind driver can drop below the railhead and cuases problems.
If it’s easy to swap out the drivers, then getting a second set to replace the blind ones may be feasible. In any case, you’ll need to take the thing apart, turn down the flanges, then requarter and reassemble accurarately to run, which is trickier than it may seem.
The leading and trailing trucks also need enough sideplay to make this work. Are you certain they’re not already a factor here? Because if they are, then fixing the drivers doesn’t really solve the issue.
Typically, the center 2 sets of drivers would be blind.
If you don’t want to disassemble the locomotive, you can apply power to it and file down the flanges as the drivers turn. If you’re careful and don’t apply too much pressure this can work.
Personally, I would store it until you have trackage with large enough curves to run it.
Good luck
Paul
Hi Terry
I have the very same problem with the Bachmann GS4s 4-8-4. I have 6 of the Bachmann Plus series and one new DCC. I took off the flanges of the two middle drivers on one of the Plus locomotives and it was a waste of time, it still derailed in Atlas 18” radius turnouts. I have tried everything I can think of to “fix” the problem without success. I returned a Plus to Bachmann for repair and for $35 they replaced it with a DCC locomotive. Before they returned it to me a Bachmann employee called to tell me that the “New DCC model” would not negotiate less than a 22” radius.
When I received the new locomotive I measured everything and compared it to my existing 4-8-4s and they are exactly the same frame and wheel set so . . . . . . I gave up solving my derail problem.
My derails are all in Atlas 540 & 541 turnouts in my yard, at a creep they do not derail so the fix for me is a super creep through my yards (like it’s suppose to be). My minimum radius out side of my yard is 26”.
If you want to find the problem, remove motor and push around 18" radius curve both ways and note where the problem is. Have seen problems as simple as a connecting wire being out of place or the driver hitting something like a cast detail.
Before getting into heavy duty locomotive modifications, I would double check my trackwork. Steamers are fussier about track than diesels and big steamers are fussier than small ones. Keep some records, say a Post-it note note stuck to the layout at each derailment location. If the derailments always occur the same places, then you have some problems with your trackwork. I have operated 8 coupled steamers on 18 inch radius curves and Snaptrack turnouts without trouble. I haven’t tried it, but I’d expect a Bachmann 4-8-4 to operate on 18 inch radius.
If some record keeping fails to point a finger at specific bits of trackwork, there are some other things to check before blind flangery. Do the usual checks of wheel gauge with your NMRA gauge. Eliminate the possibility of pilot or trailing truck problems. Remove the pilot and trailing truck, and test run the locomotive as an 0-8-0. If it stays on the track less pilot and trailing wheels, then you know the problem is with either the pilot or trailing truck.
If you still want to proceed with blind flanging, a serious hazard to your locomotive’s health, so be it. You want the blind drivers in the middle. The obvious method, powering up the locomotive and holding a file to the flanges is perilous. The locomotive gears and bearings are NOT strong enough to take much of this. Safer is to use a Dremel to do the cutting, that puts much less pressure on the locomotive’s works. Better is to rig something up so the Dremel is underneath the locomotive so that grit and grinding swarf fall to the floor rather than into the locomotive’s works.
Good luck.
Very good comments from all. Thank you!
I’ll try all the pre-grind suggestions, like removing trucks (0-8-0) and taking notes. My “power & file” method may not be such a good idea.
eBay might be better (or just let sit and make sounds).
Or widen your curves.
Or, if you like it, museum display scene… And they converted it so there is just enough that they can signal the whistle for the kids.
Trust me on this one.
(One museum near me used to do just this, have just enough steam to blow the whistle, and just enough heat to make the area warmer in the wintertime. Still cold, but, not freeze your behind off cold.) They have stopped this now, as it would cost to much money to inspect… But, steam whistles also blow with compressed air… Nice way to incorporate a industrial sized air compressor unit, have hoses lead to the whistle, now, watch the kids all smile…
(They did do just that for 2 years, but then their compressor broke. They gave up the idea then… Boy I miss that whistle!)
I have a few locos that I can run at our local club because of the tight curves on my layout. This works fine until my next layout change.
Have a friend that runs Bachmann 2-8-4 Birkshires (2) through Atlas snap switches at speed all day long. Don’t think he has ever had a derailment.
I don’t doubt it, but that’s a different eight-coupled loco. Similar steam locos can have very different min R.