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Subject: Sn3
The Tyco/Mantua "HO" Ten-Wheeler is a Southern Pacific Narrow Gauge prototype. The locomotive is actually Sn3-1/2. It takes very little to make it Sn3. Here are comparisons to narrow gauge ten-wheelers:
(Click Images to Enlarge)
The Mantua loco matches the May 1983 Model Railroder plans in overall dimensions of this SP narrow gauge ten-wheeler.
South Pacific Coast Ten Wheeler from the Jan/Feb 2007 Narrow Gauge and Short Line Gazette.
South Pacific Coast Ten Wheelers from the Nov/Dec 2009 Narrow Gauge and Short Line Gazette.
South Florida Ten-Wheeler from the Taplines website
The Tyco/Mantua Ten-Wheeler has been out of producton for almost 15 years but can be found at train meet and on e-bay for $25-50 dollars. Look for one of  the older ones.  The ten-wheeler is the easiest conversion to Sn3 because it doesn't have shouldered drivers. The drivers can be just pushed farther on the axles. All it needs is new domes and details.

The new "Red Box" versions have the can motor but the driver axles don't have knurling. That is the one I converted. Without knurling one of the wheels was free. I added a knurl with side cutters and re-mounted the driver with a NWSL quarterer. The side rod screws were also ACCed into the drivers.

Yardbird Classic Trains has a can motor for the 4-6-0. This addition plus all wheel tender pickup will update the drivetrain. It is needed for the conversion.
Phase 1 - Let's Get a Loco Running
Click here to get a Sn3 Locomotive running
Tools and Things Needed
Besides the loco I used the following:
A pair of Tichy archbar trucks buy the ten pack they are a lot cheaper
00-90 Round or Binding Head Screws
2-56 Flat Head Screws
2-56 Washers
2-56 Round or Binding Head Machine Screws
0-80 Round or Binding Head Machine Screws

I buy 3/8-1/2 long screws and cut them to length the screws can be any material, the nylon are cheaper.

Kadee #5 Coupler Centering Springs

A vise is need to hold the frame while filing, I like this Harbor Freight one.
A jeweler's saw is must in working metal, hobby saws don't cut metal well

Several files especially the 11" mill file for narrowing the frame and a file card, that dog brushy thing is needed to clean the files of chips.

Set of 60 plus drills

Harbor Freight has a 1-60 set

MicroMark has a 41-60 set

Not shown 45 deg Countersink


Fractional rule

NMRA Sn3 Gauge

00-90, 0-80 and 2-56 Taps

Pin vices

#2 socket wrench


Screw drivers

Motor Tool

I used a chain saw sharpener bit to grind away PCB copper and the circular saw style cutter works great

Wire Stripper

NWSL "Puller"
Rubber Cement


Smooth Jawed Pliers


Neolube if you use Bachmann Wheelsets

Electrical Tape

Soldering Iron

Rosin Core Solder

Rosin Flux





1/4" Hole Punch

.040 Styrene

Detail parts are available from "The Supply Car". Detailing will be covered in future articles. The important aspect of railroading is an inexpensive good running locomotive.  Less expensive Sn3 alternatives will be covered in these pages.

The prototypes covered will be non-Colorado which is where the site's interest lie. There are commercial models covering Colorado to death.

As always these articles are presented as a "what I am doing" rather than a "how to". What is on the site is what I am doing and it is all that I am doing.

The most indespensible tool in my workshop is my drill press. Get one, I would show you a picture of mine but the workbench is a mess. Not like your workbench though.
From Oso Railworks, Inc. (NWSL)

Sn3 26in/110 Point 3/32in x .900 axle, insulated one side, weathered, non-magnetic (4/pkg) (Grandt/OMI)
Item #: 37744-4