I recently started working on bringing a “new” loco into the roster. It’s a Mantua Lindbergh Special 4-4-2.
I know there are at least a few people here who run 4-4-0 locos, and was wondering if you had this same problem, and if there is a way to overcome it.
What is happening, is that as soon as one of the drivers encounters the “gap” in a switch frog, where one rail diverges, it falls into the gap, very noticeably.
I assume this is because on a six coupled or more set of drivers, the other drivers are helping to keep the entire set level.
I checked the wheels and they are in gauge. My next step has been increasing the spring resistance on the lead truck. This has effecively shifted the problem from the front driver to the rear, and although not quite as bad, is still definately there.
At this point it appears that a fine and potentially tedious excersize in balancing the weight over the drivers, and balancing the spring resistance on both leading and trailing trucks may be in order.
Am I right?
This sounds similar to the type of prblem the real locomotive builders had and will affect my resulting “tractve effort”.
Thanks.
Forgot to mention that most of my switches are Atlas custom #6 with a few Walthers/Shinohara crossovers and curved units and yards are a mix of “snaps” and custom #4. Problem is present on all.
If your wheel flanges on your locomotives and rolling stock are of a consistent depth, a solution is to lay strip material in the frog so the depth of frogs is the same as the flanges so wheels ride on their flanges while crossing.
My bet on the real problem: the flangeways are too wide and/or the wheel gauge too narrow. If you look at the picture, if the wheel is sufficiently wide, and the flangeways sufficiently narrow, the wheel tread is always properly supported all the way through the frog.
NMRA recommended practice is that the wheel tread width be at least twice the width of the flangeway. NMRA specs for HO turnouts are flangeways between 0.040 in and 0.050 in. The larger dimension works wi
What brand turnouts are you using? I have noticed some brands have huge flangeways for the frogs, older Atlas snap track and customline have some huge flangeways to the frogs and have always seem a bit rough when running steam thru them, 4 axle diesels will also bump thru them but not as noticiable as a steamer. Layouts I have built in the past used either Peco or Shinohara(walthers now) turnouts with excellent results. Mike
Interesting points, especially from Fred W. I would prefer not to add material to the flangeways on all 40 plus turnouts to fix a problem exhibited by only one locomotive. I would also prefer not to hand lay turnouts, for the same reason.
My turnouts are very recent code 83, the Walthers are new enought to be DCC freindly. I have “fixed” a few of the Atlas Custom #6s by draw filing the frogs, which were about a milimeter too high. This should have also created a reduced the flangeway depth on those.
I did check the wheels for guage, and to my pleasent surprise, they matched NMRA spec. I will definately check the tread width, but don’t know what I can do about it. I doubt this Mantua peice has proto 87 treads. I will also check the guard rail position. IMO that might be the least stressful fix.
I did breifly have both a Bowser and an MDC 4-4-2, but can’t remember if I ran them enough to notice the problem.
I really only need this loco to pull 2 specrtum P70 coaches and a Walthers B60 or R50 on level track, so maybe I can get a balance with my spring and weight idea. I realize that this Mantua is old school technology, but it is a relative “high-line” peice with a can motor and gear box.
I’m still interested in hearing ideas from others, especially anyone with a newer model like a spectrum 4-4-0 to see if this is an issue for them, or anyone running a Mantua 4-4-2.
A very in depth but reasonably easy to understand analysis of practical application of different sprung suspension systems on scale locomotives with considerations for balance, tractive effort, tracking and center of gravity.
pretty cool, even though it kind of skipped over my wheel arrangement.
