Taking a stab at it.

From what I read about others experiences it seems as though you have three options. The first is to add a bean bag to the top of the engine and see if it continues to stall over rough track or switches. (Really) There probably isn’t much room to add weight in the shell but if this solves the problem it might be the easiest of the three solutions. 

Second is to swap out the decoder with one that is compatible with a stay alive (keep alive or capacitor added). If you have been reading these blogs for long then you will know how to search for a diy solution using the same decoder (#3 solution) but it may require giving up the cab interior to make room. 

I remeber watching SW1500’s run paired in San Pedro. If you haven’t considered this then physically mu’ing them together would give you more wheel pickup. Or, use a dummy to install an NCE Dead Rail receiver and a battery. Go wireless with a CVP T5000 Throttle and never worry about contacts again. 

Craig, another solution

Craig, another solution besides the ones Neil mentioned is the addition of spring between the contact area and the wheel sets. Nelson has some nice photos of his method and it looks like the best I have seen. Also there are times the square bearings do not do as they should and I fixed the issue with thrust washers on the axles where there was excessive play.

I found the video covering this. The springs made using wire start at about the 12 min mark.

http://model-railroad-hobbyist.com/node/16868?page=1

@ Craig

Rumor has it that Rob will fix most anything associated with model trains if you drop it off...

Might be worth a visit!?!,.!

Nick

Thanks for the tips

@Neil, the loco in question isn't mine.  I'm replacing the existing QSI/Paragon decoder with a Loksound decoder so that it runs and sounds better. So getting too fancy with keepalives, extra weight, extra unit, etc. isn't really an option.  Although if it was mine, I'd be all about getting a second unit.  Gotta have pairs!

@Rob, the pickup wipers shown in the video is close to one idea that I had thought about. I just need to source some phosphor bronze strip or wire that I can use. I think I know how I can adapt that idea to the newer pickup design.

@Nick, always worth an excuse to go visit the gang at ETMRC! 

Craig

Wire source

Tichy sells phosphor bronze spring wire.  My preference for wheel contacts is the 0.0125" size, part # 1106.

Contacts

Craig, I got mine from

Craig, I got mine from discount model trains in Arlington, if you are going into the metroplex. Side bar some of us are thinking of going to visit a guy in Alverado who had his layout on the open house tour during the last train show. Paul was talking to him in discount model trains a little while ago. The guy has a huge layout under construction. I saw one of his videos and it has a 1900 foot main line if I recall correctly might be more. If we wrangle a time and try and see about an op session would you be interested in going along?

Nick, you likely need to move

Nick, you likely need to move to Texas you would fit right in around here.

@Steve, thanks for the link

@Steve, thanks for the link to the other thread.  I completely missed it, even though they are discussing the same issues I'm having here. I like the idea of the O scale coupler springs. I had thought about doing something similar, but wasn't sure what spring I could use that would be large enough but still soft/light enough to work.

I ordered a roll of phosphor bronze "Artistic Wire" from Amazon to try out.  However they don't specify what hardness it is, I hope it's not "Dead Soft".  If it works out, that's a whole lot of wire for fairly cheap.  If not, I'll have to find something else to do with it.

Craig