I have a Lionel GP-9 vintage 1999 (6-18879) that suffers from severe wheelslip. When pulling only 4 fairly light cars it will randomly stall-- the driving wheels are turning like mad but not getting any traction. None of the obvious things apply (dirty track or wheels), and there are no bad spots on the mainline where it will consistently spin. It has magnetraction but no traction tire(s) and a pullmor motor so it should perform much better than it does. It’s humiliating but my lowly 2034 will eat its lunch!
First I thought gear train was messed up (it does have some plastic gears), but all seems well there. Then it occurred to me that the center roller may be sticking somehow and causing a “high center” condition, but it will freely pivot way up into the truck frame.
Are you using an iron/steel based track? Magnitraction is only good on iron bearing metal track. Stainless and nickle based will not work. Only similar condition I’ve had was a jambed motor locking up one set of trucks while the other set spun away.
Is it a one motor version? I had a one motor version of a Lionel GP-7 from the same time preiod and it was a total dud for pulling power. If it is a one motor version sell it on ebay!
The type of track that you are using is critical with magnetraction as Roger has stated. I have 2 of the R.I. GP-7’s with the single pullmor motor and magnetraction from the early 2000’s and it does OK on my tubular but still nowhere near as strong as my old Wabash GP-7 pullmor w/magnetraction from the 50’s. Maybe part of the problem is the magnetraction itself, not near as strong as the older version.
If I can locate the parts I plan on converting my R.I. GP’s to traction tires instead of magnetraction, no stock at Lionel but they did give a couple of leads for sources.
Plain old o gauge tubular track; acts the same on fastrack as well. I noticed the magnetraction isn’t as strong as a postwar version, but still, a liteweight 2034 with no magnetraction will pull more than twice as much as the new GP. So will a single can motor cheap Geep! It just ain’t right!
I was under the impression that Magnatraction was really meant to help keep the engines from leaning around curves (reducing fall-overs), it isn’t really powerful enough to provide ‘anti-slippage’ traction. The traction tires provide that. I have a modern diesel that has Magnatraction and traction tires, and it pulls like a beast of durden!
I noticed that you said your engine doesn’t have traction tires. Is there anyway you could replace two of the drive wheels with wheels that have traction tires? Also, how heavy is the engine? That can play a HUGE roll in how much it can pull, but without the traction tires I can’t see the GP7 pulling very much at all.
OK, some good news for me and possibly others. Looking at the engine off the track I noticed the pickup roller under the power truck would hang down much farther than the one on the plain truck. Also, the spring on the arm was very strong. So, I first monkeyed with the arm pivot assembly until both rollers looked about the same, then took a winding off the spring (didn’t cut it, just unwound it a lap) to relieve some of the upward pressure the arm was exerting. Bingo, no more spin! Apparently the spring was actually powerful enough to partially unload the drive wheels and cause the spinning.
Thanks to y’all for your suggestions; I knew there had to be something else, tho. The engine isn’t exactly a liteweight–it has to weigh as much as a postwar-- and with the same basic configuration as a PW model (plus all the TMCC boards and such) there was no obvious, logical reason for it to be so anemic.
I suggest that you who have had similar problems check this out. Those springs are mighty strong, and I can see how adding weight would help altho it would be only a remedy for the symptoms and not a cure for the disease…
BTW, Lee, I had considered selling it on Ebay but that’s where I bought it! Took awhile to find, too, so thankfully I’ll be keeping it.
Brent, as originally envisioned, Magnetraction was touted as a traction aid (More Speed, More Climb, More Power!, said the old catalogs) with the added benefit of keeping the engine right side up as it flew around the curves.
Sula, How about adding the fix that you did, in detail, to the “Sticky” opening thread at the top of the page. Maybe it will be of assistance to someone in the future. Congrats ! [tup]
Huh??? Lets say a springs’ total rate is divided evenly (linearly) over each coil, for example, 10 coils on a 10 pound spring. Remove one coil (one pound) and you have a 9 pound spring, or a 10% reduction. You have less spring trying to do the same work; the rate is fixed, it can’t compensate by pushing harder! Try it and see. Gunsmiths frequently remove coils from springs to lighten up trigger pulls and such.
BTW, I didn’t cut the spring anyway as it needs two tails. I “unwound” one end one wrap around the pivot pin.
“as the number of active coils decrease, the spring rate increases.”
look it up. it can readily be found on many sites on the web.
Another way to look at it is: imagine the spring is unwound into a straight wire. that wire is supported at one end and the wire is horizontal. A given weight on the free end will deflect the spring a given ammount giving lbs/inch. now cut off some of the free end of the spring wire. put the same weight on it and observe: less deflection, i.e. higher spring rate.
more than likely what happened is, as you unwound one coil, the tails did not come out in the same relationship as they originally had. then when reinstalled has less preload. less preload, less intial rate, less lifting of the locomotive wheels, slipping solved.