The PRR Life-Like SW9/1200 engine that I received from Ed looked great but was kind of a noisy runner. It sounded like my old washing machine. I fiddled with the contact arms on the trucks and pickup strips under the walkway but it really didn't help much. Then I read somewhere that the problem was that the plastic worm gears were not cut deep enough and that it was suggested to replace them with metal ones from either Atlas or Kato. I went with Kato since I needed another part from them anyway.

The Kato worm gears I ordered were part number 926510 which came as shown on the left.  I discarded the black bearing blocks and universal connectors until I was left with just the metal worm gear attached to it's shaft.  I put it vertically in a pin vice and tapped the shaft down until it was even with the top of the gear, then popped the shaft out using a punch that was just a tad smaller that the shaft diameter. The punch was made out of a cut-off dental pick that I had used before in my steam engine repair days.

The SW9 was disassembled and the plastic worm gears on each side of the motor basically came off of the motor shaft just by hard hand pulling them.  The new metal gears were a good fit and only required a little tapping to get them on the ends of the shaft and to seat them so they were even with the ends of the shaft. Didn't even need to use Loctite 609 on them. A little white grease on the new worm gears and the engine was reassemble.  The improvement in running characteristics was simply amazing!  The engine is very quite and runs great.

Since it now runs much better, I thought it deserved a little cosmetic improvement with the addition of #905 Z scale couplers.