Bachmann K4 Turnout Snag

[prr7161]

I ran into a strange issue with a K4 on a handlaid turnout (FastTracks).  When pulling through in the trailing point direction, something on the trailing truck seems to be snagging somewhere, but I can't see what it could be.  The loco runs through the turnout fine in forward and reverse in the facing point direction, and backing through in the trailing point direction.  The snag is occuring when the trailing truck wheels are just at the gap at the frog, and the trailing truck frame is over the guard rails.  The trailing truck wheels are in gauge, and no other rolling stock (so far) has had trouble like this.  The trailing truck wants to kick to the right (i.e. away from the frog) but is more likely to just snag and hold than derail.  Any ideas?

[Jim Costello]

prr7161  The FastTracks jigs can be a bit tight around the frog area (even though they are in gauge). I have built more than 200 over the past 6-7 years and in several I have had to ease out the gauge at the frog and a few more on the guard rail. I use a small flat screw driver
and twist it using the frog rail or outside stock rail as a fulcrum or lever point to as I apply the soldering iron to the joint to ease out the rail. I can visually see the movement and it may only be a very small fraction of a movement to solve the issue.
Keep us informed.

Jim

[prr7161]

Thanks, Jim!  I've definitely run into the flangeway issue you are describing - much as I love the FastTracks stuff, there are one or two spots on the fixtures that are a little tight for most equipment.

Since this issue was bugging me, I started taking the loco apart a bit just after posting.  Once I had the trailing truck off I could feel the snag point.  Turns out the trailing truck casting had a bit of wedge-shaped flashing hanging from the forward spring detail.  The springs are outboard of the rail and the flashing rode just below the railhead, enough to catch the inside angle of the frog.  When the truck would reverse through the switch, the shape of the flashing would ramp it up over the converging rail, but forward it would stick tight.  A little work with the file and it's golden!

Something to watch out for I guess with these locos.

[Jim Costello]

I was going to mention to you to check out this same issue. In the 'Golden' years a lot of wheels had this same problem with a bit of plastic still attached to the (insulated side) wheel. I picked up a 2nd  hand Rivarossi pacific that this problem with a pilot wheel. The owner
had made a good long flat spot down into the brass.
Other than wheels in gauge these are the two items to look out for with such issues.

Jim
Modelling the NH down under
NHRTHA #l82

[mike_lawyer]

I think the N scale locomotive encyclopedia mentions this issue with the Bachmann K4s... A couple swipes with a file and you should be good to go.