Hi Jim,
NWSL has a drop in replacement. This was a common problem with the B1a's and a lot of the early AJIN and Korean brass.
Like Norm Abram says, "The five most expensive words... And while you're at it."
Since you need to remove and replace the axle gear, don't skip re-quartering all of the drivers. Having done 100 or more of gear box replacements, I've found 2 out of 8 drivers are usually correct; at least the drivers found tight on the axle... Loc-Tite the drivers, crank pins, and solder the eccentric crank to the driver crank pin but only if you have a resistance soldering set. If not, Loc-Tite and let it set overnight without touching it.
The last thing to check is rod slop. If the engine was the one in a hundred that ran longer than an hour or 10' before the gear box shredded, the holes in the side rods may be 'wallered' out. Most likely, they're not but given the age of the model and its unknown service history, it's something to check.
The last thing to add are NWSL's Thrust Washers (Bearing) for the driver/crank pin to keep the rods separated and the eccentric crank spaced perpendicular to the crank pin. Most brass engines at this stage of the game are mashed together for final assembly. A few washers maybe needed to square everything up.
Take your time and when you get to this stage, the mechanism should roll without any binds when pushed with an 0-5-0. If you feel a bind, look for the jerk in the rods while pushed along the test track. The jerk is the problem area (like everywhere else). But you shouldn't if you followed the steps above and the engine will be smooth as silk. Add a brass flywheel and replace the drive line rubber hose.
The best thing you can get from NWSL with your parts order is their book, Upgrading the Running Performance of Brass Steam Locomotive #512-9 at $10.00. They have another book, NWSL Brass locomotive clinic Illustrations and repair/upgrade ideas but I haven't seen it and no price is listed. The material found within is applicable to all scales.
Everything NWSL does is first class and light-years beyond factory cheap.
Happy Easter!
Randy Danniel
Fri Mar 25, 2016 9:04 am (PDT) . Posted by:
Thank you for the suggestions. I'll try the gear form.
Jim