MN Bombardier Coaches in HO

Sorry if this has been asked already... I'm new to the forum, and there are so many topics, it'd take me days to see if my question has already been asked. I'll risk being flamed to just ask my question in the hopes of moving on with my layout plans.


I've got a collection of the Walthers 85' commuter coaches... the ones that probably everyone and their grandmother has, and there are always more to be found on eBay. My main problem with these cars, is that they're SO long, it's nearly impossible to get them to take a curve without derailing! I'm using 22-inch radius Bachman EZ Track (yeah, wimpy, but I'm lack the skill and patience to be laying down cork roadbed, nailing in track, etc.). This is very frustrating because with a standard 4x8 piece of plywood, curves alone eat up most of the space. I'm actually using two 4x8's and a 2x8 connected together in an L shape... was hoping to do a "bent wishbone" type of layout where the tracks would circle around at the ends, but come together nice and parallel for "Croton-Harmon" near the middle. Unfortunately, the wide radius required of these coaches has put a stop to those plans. I thought about doing a point-to-point layout, but when testing that idea out, these same coaches seem to derail when being PUSHED through a switch. They can be pulled through switches just fine, but God forbid I try to push them with the Bombardier cab facing forward.

Any advice on possible solutions? I know that "build a bigger table" is an obvious option so I could use wider-radius track... but not too feasable without the costly prerequisite of digging a bigger basement. I thought I heard that there was something one could do with the trucks and/or couplers of these coaches, which would help them stay on track through a curve... but I can't seem to find those details anywhere.

I've seen pictures of Bomb coaches in O-scale... while they look very short and stubby compared to the prototype, at least they look like they can take curves without any hassles! This is a scenario where I wouldn't mind if Walthers sacrificed one aspect of realism to make the HO models a little more track-friendly... at least I'm still in the "design stage" where I can keep tinkering with different options. I really feel for everyone out there who had to rebuild major portions of a layout to accomodate these radius-hungry coaches.

Thanks in advance for any advice you can provide!

I've had a bunch of these for a while, and I picked up many over the years. I noticed that there are actually two different draft gear versions...the later versions allow more swing and thus allow the cars to negotiate a slightly tighter curve. I remember being inspired by this observation to modify the older draft gear boxes in such a way as to allow them to similarly swing further, but I don't recall the exact details of the modification...I'll have to take a look at my cars and get back to you. In the meantime...

What kind of couplers do you have installed? If you have horn-hooks, you can forget about push mode. However, I have been able to push at least 4-5 cars successfully when they are equipped with Kadee #5s. You may need a longer shank coupler (ie, #46) to negotiate 22 inch curves in either push or pull mode.

The reality, however, is that these cars really like curves larger than 22"...like 36", especially in push mode.

It sounds like the main problem here is weight, or lack thereof. Your cars might be able to physically negotiate the 22" curves, but whn trying to push them in reverse, they're being shoved outward far enough to derail because of the way the coupler forces are being transmitted along the center axis of the cars. Adding extra weight (probably going beyond the NMRA recommendation for a car of that length) would help stabilize the cars so they're not as likely to tip over or jump the rails.

Mike does have a point about the coupler mounts, too. On the early production runs, the screw-on cover that retains the pivoting coupler box is rougly a large triangular shape, but on later runs this was changed to basically a T shape so that the trucks could swivel further without hitting the angled sides of the coupler cover. Check your cars to see if any or all of them have this older cover, as it's the only real impediment to truck swing that I can think of. Be glad you're not using the Amtrak 'Horizon' version of these cars, as their truck sideframes collide with the floor-mounted triangular shock absorbers and require an even higher minimum radius!

BTW, I vehemently disagree with your comment about the scale length of the cars. The only O-scale versions I know of are Atlas O's models, and those are full-length. In this day and age of more-realistic models, I think that 'shorty' passenger cars are outdated and look pretty silly. I suspect Walthers would have lost a lot of sales had they chosen to compress the length of the cars, and those of us who stress realism would have been forced to do some kitbashing to get correct cars. It's also becoming more accepted that you need to plan your layout according to what kind of equipment you want to run. I mean, freight modelers don't run shorty autoracks on 18"-radius curves, and I don't think they'd want to either. Granted, your options for passenger cars are more limited in N scale, but usually that's the way to go if you simply don't have the space.

Regarding your layout ideas, keep in mind that switches come in varying angles as well. You really shouldn't be running passenger cars through a #4 switch, and for push-pull operation you'd want to be looking at #8 or #10. Also, although I know space is tight for you, you may want to experiment with adding spiral easements to your curves. If you're not familiar with the concept, they're basically a stretch of track in a gradually varying radius to transition between straight track and your full-radius curve. This is more prototypical and would result in smoother operation, since if you think about it, your cars are humming along on the straight track and then suddenly lurching into a 22"-radius curve, whereas an easement would allow them to shift their momentum before entering the actual curve.

(In physics/engineering terminology, we're dealing with an abrupt change from linear motion to uniform circular motion. The associated change in the magnitude and direction of the acceleration vector is large enough to exert a sideways normal force that can sometimes knock the cars off the track, much like the way you get squished to one side if you take a turn too tightly while driving. Sorry if this is way over anyone's head, but I figure I haven't been taking Physics and Dynamics classes for nothing!)

What about banking tracks? Is this possible, and if so, how many degrees(in HO and N) can you go? Thanks...

You really need wider radius curves in order for your passenger cars to look right and to operate properly. Most modern passenger trains just weren't meant for table-top layouts.

-otto-

Mine will be receiving type H couplers, as that's whats on the prototype.

Three cars are the max for push mode on my layout with 18" curves. Also check the coupler on the cab end of the cab car, it might droop a bit, I've found this on MN 5174 and it snags running through the gentle S-curve at Roseville Aveune. As for the Amtrak cars, I remove the triangular shock absorbers from them and the single Viewliner on the layout. As Alex said check for the older version of the coupler boxes on the cars. All cars in the R-T-R boxes should have the newer coupler mounts. As for the outward banking on curves, I seldom have derailments even with the heavy U34CH or ALP44/AEM7 pushing.

You can always ask Sam Clarke, Coupler Conversion Specialist at www.kadee.com click on contact information, then e-mail and their
reply form drops down.
Send it to the attention of Sam. With the holiday, I suspect it will be Wednesday before you get an answer. Be specific about car information.