I am building a layout and can get by with a tighter radius when I have to as I run short cars. The weird thing that happened is I ran a larger engine around an 18" radius section (its a turnaround high trestle) and it jerked badly at both ends on the first couple of go overs. Thought it might be a bit of narrowing as it was close to the solder joints. Then it smoothed out and was fine. The reason for the post is to see if anyone has an idea as to why this might have happened and do I need to do something before I ballast to make sure it dose not return? Could it be the engine instead of the track meaning the track was still in specs but ever so slightly narrowed and something was amiss on the engine and was fixed in running.
Hi!
If you are saying that the loco bucked a bit the first time thru the tight curve but then went on just fine when it went thru the same curve again and again, well I would say something was binding and the first jolt smoothed it out. Perhaps something was in the way of the front/rear trucks.
Or, perhaps you left something on the track or between the rails that got in the way (been there, done that).
In any case, I would scrutinize the curve with an NMRA gauge, and at the same time make sure there are no obstructions or debris in the area.
Or something in the engine was binding and relieved itsef.
I would run it some more in bothe directions to make sure all is ok.
I would hazard the possibility of two things, maybe not just one, but both happening: Maybe one axle was a bit out of gauge, and the ‘encounter’ with the joint pressed it back into a better separation. Also, if you had an unknown rough or high point at the joint, or with the solder, itself, the ‘encounter’ may have relieved it to a healthy extent. Solder is soft, and maybe it got sufficiently pounded upon that first impact that it is no longer an issue.
Sometimes, too, a foreign object, say a stray piece of sprue, tree branch, ballast, plastic tie, whatever, gets laid up against the flange path and the first encounter is kind of bumpy. I keep finding all sorts of belly-up sow bugs on my layout. They aren’t exactly soft and cuddly…at least, none of my steamers thinks so. [:S]
Crandell
Was it just one engine or a few different ones?
I had a new Athearn SD 50 that would jerk in turns when I first got it. Wheels seemed OK when I check them. I kept running it and it is now fine.
Cuda Ken
No a had used another engine before this one and if it had happened at only one end, I would have looked for a problem and fixed it. It happened at both ends, I don’t know, maybe there is a very slight narrowing but an engine should not have been able to fix that, maybe the engine was out of whack from hitting something and it was not a problem till it got to this curve. To make sure the world was right I got out another engine to test, all fine. It’s a mystery, just thought someone might have had something like that happen before and it came back and the fixed it one of many ways.
Could also have been a spec of some kind of foriegn material somewhere in the gear train that worked it’s way out. Or maybe just in a position now where it’s not catching between gear teeth. I once had a similar intermittent hitch when a piece of hard material got caught up in a motor armature. Thing would operate fine for hours at a time, then would drive me crazy when it moved around just right to catch between the motor frame and the armature field piece.
I’ve had a long career trying to track down intermmitents, both as a mechanic and in product development engineering. Can drive one nuts. Wife sometimes says that explains things. Not sure what she means.
Best one was a car problem that we worked on for over a week. First went out with the vehicle owner, me driving, no problem. Tried everything we could think of for a week. Gave it back to the owner. He went out to the car, started it, backed out of the parking space, then came right back in. It was acting up again. Turned out this 80 something year old gentleman was efectively leagally blind. When he wasn’t sure of oncoming traffic such as at an intersection, or similar situations, he’d floor the throttle, torquing the engine on it’s mount, driving the fan blades (older car, fore-aft V-8 engine) into the fan housing. Somehow, he hadn’t broken the engine mounts. All we could do was change from a 6 bladed 18" fan to a 7 bladed 17" fan as a stopgap…
Month later, the intermmitent problem was permanently solved. Gent had a collision (can’t call the result of egotistical stupidity an accident) and had to go to court. Judge asked why he wasn’t wearing glasses, if his eyes were so bad. Gent said he was a man, and men didn’t need glasses. Judge said either he’d get glasses, or give up his license. Gent pulled his driver’s license out of his pocket and put it on the bench. He won. He defended his manhood.