PRR RS-1 - Construction: Impressions
09/26/2009
When I first announced to the Yahoo S-scale mailing list that I had switched from N-scale to S-scale, one of the "elders" of the group warned me that patience is required when modeling in S-scale. I don't mean to make this is a big issue, but it took me exactly four months from the date I asked Railmaster Hobbies to send me an invoice for the RS-1 kit and the matching North Yard chassis until I received it at my home. My point, here, is not to harp on the company, but rather to realize that it may take some time to get your kit. In other words, plan ahead. I was no real hurry, so no harm done.

The owner of Railmaster Hobbies in Los Angeles is Jeff Smith and he was easy to work with. A member of the list had bought this kit before I did and recommended that I'd ask Jeff to check the box for any missing parts. It turned out that the front cab wall of the kit was missing, and it had to be ordered from New Zealand, where the kit is produced. I suspect that was the source of the delay. However, after several prompting e-mails, the process was moved along and I eventually received the kit and chassis. Both arrived in good condition, and I am happy with my purchase. I also enjoyed communicating with John Agnew, the owner of the New Zealand operation. Needless to say, this is the only place where we can purchase an RS-1, but I would be happy to deal with Railmaster Hobbies again if/when I need another kit.

This is the first time I have ever built an engine kit. I have also never worked with a kit that is all metal. The first time I opened the box I noticed that there were a lot of parts to the kit, and I thought "Looks like fun!". When I finally sat down to actually begin to work on the kit, I became overwhelmed. This is not a kit for the beginner or the faint-of-heart.

The instructions that come with the kit provide only high-level guidance as to what you might work on. In two sentences there's enough work for two or three evenings! There is no such thing as a detailed step-by-step guide. You have to kind of figure it out for yourself. I, therefore, highly recommend that you get a copy of Dick Karnes' article in the April/May 1992 issue of "3/16 'S'cale Railroading" magazine (you can obtain a copy of his article from the NASG Library; I received my copy electronically very quickly). His article provides additional notes, but it is still not a step-by-step guide.

I recommend you gather lots of prototype photos of the engine from different angles. The instructions that come with the kit have three black-and-white photos of different U.S. prototype engines from different angles, but I don't think they are of good enough resolution to be able to make out the smaller details. Also, your particular prototype may have added details that this basic kit doesn't provide, so some scratch-building may be necessary.

Most parts will have some flash in odd places, so be sure to test-fit each part and verify, by running your fingers over the part, that all the flash is gone. A number of the parts were bent or wrapped. This is due to the material used, but, since the parts are easily bent out of shape, they are also easily bent back into shape, usually just by using finger pressure.

This first photo shows the packages as they arrived. The box on the top contains the North Yard chassis, and the other box contains the parts that make up the kit of the body.
Construction: Impressions
The North Yard chassis comes all pre-assembled. It is a relatively simple construction. However, I wouldn't want to built it from parts, though. It consists of a single sheet of metal to which two gear towers are mounted. A motor is screwed to the metal plate and two sets of universal joints connect the motor's shafts to the gear towers.

Electrical pickup is provided by the wheels, which mechanically make contact with the side panels of the truck/gear tower. Each side panel is electrically insulated from the side panel on the other side of the truck, of course. A wire mechanically attached to the side panel, via a small screw, routes the track power to the motor. All eight wheels provide power to the motor. There are four wires going to the motor. A red and a black wire are soldered to the motor's terminals, and another set of red and black wires are connected inside the motor. I don't know why those weren't just soldered to the motor's contact, but I did find out that the two black wires are connected to each other (internally, I suspect). Each set of wires is connected to one truck/gear tower. Testing the unit for electrical continuity, I found everything checked out perfectly.

The motor is a NWSL #22363-9 (no longer listed on their web site). This is a 12-volt, 5-pole, 22x36mm, with 2.4mm shaft, can motor. According to the old NWSL web site, the motor has a stall current of 1.4 amps, and a no-load RPM of 11,000 at 0.07A. The label on the motor states 9,600 RPM. North Yard states that the maximum load current is 0.47A. The motors are flagged as DCC-compatible. Based on this data, I think any 1-amp DCC sound decoder will work for this motor. I briefly tested the motor and it is indeed very quiet, as stated on their web site.
Construction: Impressions
External Reference:
The North Yard chassis does not come with flywheels, which I consider to be critical for smooth operation. I don't know why the chassis didn't just have the flywheels as a fundamental part of the unit; it doesn't seem to be that much more money. I asked Jeff Smith of Railmaster Hobbies at the 2010 Sn3 Symposium and he didn't know either why the North Yard chassis doesn't come with flywheels. One reason I can think of is that the size of the flywheel might affect how well a body kit fits on the unit. This chassis is used for a large number of different engines (both US and New Zealand prototypes). The old NWSL web site suggested the 403-6 flywheel for this motor. The shaft on either end of the motor has a diameter of 2.4mm (3/32"). The 17mm outer diameter flywheel is the only one that fits, as the 25mm outer diameter flywheel would interfere with the metal plate of the chassis.

The wheels on the trucks appear to be low-profile scale wheels, because they have the same flanges as the scale S-Helper Service truck wheels I have. The axles are a scale 9'-4" apart, matching the prototype drawings of the RS-1 exactly. The wheels are a scale 40 inches in diameter, again matching the prototype drawings. This looks like a very good and accurate drive unit. I'll have to see how it performs once I have a DCC decoder installed.
Construction: Impressions
The kit of the RS-1 body appears to be identical to the way that Dick Karnes described it in his review of the kit in the April/May 1992 issue of "3/16 'S'cale Railroading" magazine. The first photo at the top of this page shows the simple color photograph Dick describes in his article. The photo shows the SW9, RS-1, and S2 kits that are available. The photo of the RS-1 is fairly useless for kit construction, but it does give some color to the plain box. Inside the box, shown below, we find the two-sheet instructions, a collection of plastic bags containing the smaller parts, the main body parts, and several lengths of brass wire.
Construction: Impressions
Here's a photo of all the kit's parts removed from the box. I suspect that the one labeled plastic bag is the one that needed to be sent from New Zealand to complete the kit. A quick inspection of the parts seems to indicate that they are all in good shape. The parts are mostly pewter metal, and thus very heavy. This should produce a nice, heavy engine, which will help traction. A lot of the more delicate parts appear to be bent, but they should be able to be straightened out carefully before assembly.
Construction: Impressions
This last photo shows the instructions sheet. The page shown in the photograph shows the exploded diagram of the parts, both side profiles, and the front and rear profile of the engine (a top view is available on the last page). The drawings are marked as "1:87" scale (i.e. HO-scale). The inside pages provide a brief history of the engine, the kits parts list, general instructions, where decals can be purchased, and some black&white prototype photos. It appears these instructions are identical to the ones Dick Karnes described in his article of 17 years ago. Whether that is good or bad, I don't know until I get around to building this kit. Dick considers his article to be supplemental to the instructions that come with the kit, so I will definitely be referring to both as I build mine. I hope my pages on this web site will help future purchasers of this kit to build theirs.
Construction: Impressions