Surging down grade, DCC

Model Railroader Electronics and DCC
1

Hi everone

I can’t seem to pull up the post on surging, probably to old. The engine in question is a new spectrum steam with factory DCC. With cars behind it going down grade it keeps surging and slacking.
Any thoughts on my problem?

Thanks [%-)]

Lee

2

I don’t know if spectrums have it but back emf can cause that. If it’s an option try turning it off.

3

Brand of loco, model of loco, did you install decoder, factory decoder?

Rich

4

Lee

Try giving it a little momentum in CV3 and CV4. Start out with a little and add if no changes are noticed. If that does not work look to a mechanical situation like a driver out of quarter.

Pete

5

DCC or no DCC, you have problem with the drive mechanism. There is movement in the worm gear. I refer you to this thread for answers on how to solve this issue. Don’t mess around with the decoder settings before solving the drive issue. You’re simply masking what is the true problem.

http://cs.trains.com/trccs/forums/p/156126/1722426.aspx#1722426

6

Bachmann “DCC On Board” locomotives use a cheap, watered down Lenz decoder that does not have BEMF. The surging could be caused by a flaky decoder, but is most likely too much free play in the worm gear.

7

Guys

I think you are probably right about the worm gear having too much play. I have an Email in to Bachmann. We’ll see what happens.

Lee

8

FWIW, I’ve had this same problem with a couple of Athearns running them with DC. It went away over time and was definitely a worm gear break-in problem.

JT

9

I would try giving the engine some extended running time, both forwards and backwards. Especially with steam engines, it can take a while for all the kinks and flash etc. to work themselves out. Although this probably wouldn’t cause what you describe, check the siderods and valvegear too; Bachmann packs their engines pretty snugly in the box, and the rods can get bent in a tiny bit causing problems.