This old loco


Arved Grass <Arved@...>
 

Ken Clark wrote:

"Since this a KTM model, I would stick with KTM gears/driver sets.
At most NMRA conventions (and O Scale West) the inventory of
replacement parts that came from Vince Waterman's 'Trackside
Specialties' are on display. Somewhere in the mass of jumbled papers
resulting from my recent move, there is the new address and company
name, seems they periodically advertise in MR."

I'm sorry that this reply is so late, but I've had some difficulty
receiving list traffic. i.e. I've got none since I signed up,
despite confirming that I'm a member of the list, and scheduled to
recieve the digest version. I'm forced to read the digest at the
one-list website, evidently.

Ken, your response is MOST encouraging. In fact, I'd looked at my
WSM AC-4 (4-8-8-2 for the non-SP modelers on the list), and they
looked very promising.

If you (or anyone else) comes accross Mr. Waterman's new address and
company name, I'd be indebted.

The nickel plating kit that was suggested is a good one. I'll be
looking for it. I have some other projects (not train related) that
I could use this for. I happened to have a J.C. Whitney catalog, and
they have plating kits for many metals, including gold, silver, and
nickel. Except for the gold :-), they're all fairly reasonably
priced - much less than what I had expected to send the drivers out
to be plated.

Are you changing your suggestion that I go with a NWSL gear drive? I
read the above that you're suggesting I go with KTM replacement
gears. Although this model has lasted 30 years (and the gearbox
started showing signs of wear 10 years ago), I'm not looking forward
to tinkering with this model any more than I absolutely have to. I'd
rather tinker with something else :-). My primary concern is for a
smooth drive, with longevity a very close second.

Someone mentioned steel wheels - I've never complained about going to
nickel silver wheels on Athearn engines. Even with the nickel silver
wheels, they seem to out pull similar locomotives from other
manufacturers that have nickel silver wheels. Pure adhesion isn't a
real factor for most modelers, even in a club environment. A little
extra weight compensates nicely. However, I'll agree that adhesion
is an issue with steam models. It's a lot harder to get the weight
of most steam engines up so that they can pull. Super-weighting a
steam locomotive is an art form all to itself.

Thinking ahead a bit, I'd like to do this same driver treatment to my
Sunset models MT-4 and -5 (4-8-2s). The model is shipped with spoked
drivers, and most MTs had universal main drivers by the 1950s. I can
probably find loco's to model that didn't have the main driver
replaced, but then they wouldn't be typical of the time. Any
suggestions for the Sunset models?

Thanks to everyone,
- Arved
From just a little too close to CSX milepost 666, Sanford subdivision
Modeling the Southern Pacific from AC-4s to AC4400CWs.


Ken Clark
 

In a message dated 2/22/00, 5:54:22 AM, HOsteam@onelist.com writes:
<<Are you changing your suggestion that I go with a NWSL gear drive? I
read the above that you're suggesting I go with KTM replacement
gears. Although this model has lasted 30 years (and the gearbox
started showing signs of wear 10 years ago), I'm not looking forward
to tinkering with this model any more than I absolutely have to. I'd
rather tinker with something else :-). My primary concern is for a
smooth drive, with longevity a very close second.>>


First, would be to determine what is the problem with your current gearbox.
The problem areas are excessive play in the bearing surface areas and gear
wear. In the bearing surfaces the shafts are generally hardened steel, the
worm shaft bronze bearings and the gearboxes white metal. I would expect any
of the steel shafts to have the least wear. Replacement of the bronze
bearings on the worm shaft is very easy. If the bearing holes in the gearbox
are worn, a new gearbox is the answer, although the idler shaft could have
new bronze bearings fitted. The gears should wear in the following sequence,
worm gear turns fastest and only one tooth contacts the idler worm gear. The
reverse worm gear on the driver turns the slowest and wears the least (in an
idler gearbox). The idler gear is usually nylon and can be chewed up by a
bad worm gear. I would expect in most cases the axle gear to be the least
worn; so replacement of the worm and worm gear (idler gear) would give like
new performance without having to replace the axle gear. A new gearbox case
would cure wear problems in white metal bearing surfaces, without pulling an
axle gear. Be sure to use thrust washers to get a nice, almost snug fit on
the worm shaft. Excessive play between the worm shaft bearings and the worm
will cause a steam engine to "buck" when running with a train downhill, even
with a new gearbox.

The NWSL HO gearboxes (.3 mod) have smaller teeth than the KTM gearboxes,
this means less strength and more susceptible to wear. The larger .4 mod
gearboxes have gear teeth similar to those of the KTM gearboxes. I suspect
in the future these will be available with retrofit ball bearings on the worm
shaft. These gearboxes are larger than the KTM gearboxes so require
modification to the frame. But the potential benefits of roller bearings on
the worm shaft; make these gearboxes my favorite if I have to pull the driver
axle gear, especially noisy PFM articulateds like my PFM D&RGW L-125. I
avoid pulling axles at all costs, but many gearboxes are so poor that there
really isn't a choice.

ken