And yet another unusual locomotive for Atlas to have chosen for their fourth release overall and first from Mehanotehnika in Yugoslavia. Introduced in July 1968, it followed closely on the heels of the IHB 0-8-0s. The prototype was built by Alco as an option of the RS-2 locomotive for railroads that needed units that could operate on lighter track. Six wheel trucks were installed in place of the normal four wheel trucks to reduce the per axle load. Unlike later Alco six wheel trucks, the axle spacing was the same between all three axles. On later units, the middle axle was closer to the outside axle than the inside axle. Of the five roadnames offered, only the Union Pacific actually owned these engines (at least the road number is correct - 1295). The releases included Union Pacific, Monon, Erie Lackawanna, New York Central, and Southern Pacific liveries.
Back then, when I saw the introduction of this locomotive, I somehow scraped up the money (read begged for it from my parents) and ordered one right away from America's Hobby Center in New York as soon as it was in their ads in Model Railroader. There was a big difference between spending $12.98 for this and spending $19.98 for an 0-8-0, for which I had to wait a couple of years. I bought the Union Pacific version and still have it. Of course, being a true model railroader, I "improved" the appearance to make it more true to prototype as you will see in the images. Later I got the Southern Pacific version too.
I also remember thinking, at the time, that the axle spacing in each truck was incorrect because any six axle Alco loco that I had seen up until that time had trucks with the uneven spacing. I thought it was just a design error or production compromise I guess. It wasn't until years later that I learned that the spacing is correct for an RSC-2.
Interestingly, this was the only Mehano built locomotive that was not picked up by other importers after Atlas discontinued them.
The construction of these locomotives is quite a departure from the Rivarossi units. Although the body is held to the frame similarly with lateral locks, the main frame is plastic with the motor mounted horizontally in the center. The carbody is a fairly good representation of the prototype but looks kind of squat because the hoods are a little wide and short. There are also the rather obvious open vents right in front of the cab on the long hood. Of course, these are needed because the Mehano motor tends to run quite warm (OK, almost hot). A five pole, open frame motor is used as opposed to the Rivarossi three pole can motor. The motor drives a worm in a gear tower via a coupling and the power is transferred to the two rear axles in the rear truck. A worm gear and spur gears are used for this. This is actually similar, in function if not form, to present day models. The front axle in the rear truck is an idler and there are traction tires on all four drive wheels. Electrical pickup is from the outer axles on both trucks via wipers that contact the inner surfaces of the wheels. Wires, soldered to tabs on the wipers, then carry the current to connections on the motor. The rear truck is held to the frame with a pin that passes horizontally from one side to the other through the frame and gear housing of the truck. The front truck is held to the frame with a shouldered screw and nut through the front center of the truck up through the frame. The headlight bulb is soldered to the extended tabs from the front wheel wipers. Weight is provided by separate metal castings that merely rest on top of the frame and one mounted between the fuel tank and air reservoir simulations on later units. I will discuss this, and other variations, below.
Atlas Identification: Early units: "ATLAS (in the "graduated" logo) YUGOSLAVIA" molded inside of a circle on the underside of the plastic cover in the fuel tank area. Later units: "ATLAS YUGOSLAVIA" molded into the bottom of the front truck with "ATLAS" in larger letters on the fireman's side and "YUGOSLAVIA" in smaller letters on the engineer's side. There is no identification molded into the shell but I don't believe these were marketed by anybody else. Of course, if anybody knows otherwise, please correct me.
Variations: The variations are mainly divided between the earliest releases and later units.
No known variations.
No known variations in the frame itself, but there is a difference in the number and types of weights. Both early and later units have the weight that mounts on the short hood end of the frame (it stradles the shaft coupling area and rests on top of the gear tower). This, however, is the only weight in the early units. Later locos have an additional weight that rests between the motor and light bulb at the long hood end. They also have the weight that is on the bottom in the fuel tank area. As a result, later units are much heavier than the early ones.
Later units include a plastic spacer between the tabs from the front wheel wipers that the early units don't have. A short circuit deterent, I'm sure.
Early units have an enclosed rear truck while later units have slots that expose the driving gears. I can only assume that access for lubrication was the reason for this change (or maybe a gear size change due to the larger and possibly slower RPM armature in the later units). The following view also shows the weight included in the fuel tank area as opposed to only a plastic cover on early units.You can view these differences here. Click on the thumbnail for a full sized picture:
You may notice, if you have unaltered versions of these locomotives, that the traction tires, in the view above, have been changed to something (silicone) other than original. They had black rubber tires when new. The rubber deteriorated and I replaced them. That these engines originally had black rubber tires was recently confirmed when I repaired the Monon version below. The tires appear to have been untouched.
Early units have a motor that has an armature with fewer laminations (15) to the winding core than later units (18). The space between the end of the core and bushing is noticeably bigger on the early unit. You can view this difference here. Click on the thumbnail for a full sized picture: The early chassis is on the top and later on the bottom. Um, you can also see the "improvements" I made (painting the trucks, adding Kadee (MT) couplers). At least I could still change the couplers back to Rapido since I saved them!
In the image above, you can also see another variation. In the early unit, the coupling between the motor shaft and worm shaft is a two piece male-female affair. In the later unit, the two white end pieces have pegs on them with a rubber cross-shaped piece between them. Different color plastic is used for various drive line pieces too (coupling, worm, worm gear). There is red, black and white. There can be different combinations on the same locomotive. There is also a variation in the worm bearings. Some (early?) have square ones and others have round ones.
Please contact me with any additions or corrections: firstname.lastname@example.org
Links to images of the available liveries. Click on the description or thumbnail to view a full sized picture:
Remember that the U.P and S.P. examples were modified by me so units in as-built condition will not have painted trucks, painted hand rails, red stripe on the sill of the U.P. unit, box next to cab at short hood area on the U.P. unit, or modified hand rail configuration (it will just go straight to the cab) on the U.P.unit.
The Monon image courtesy of Neal Lighty.
The as-built Union Pacific, Erie Lackawanna, and New York Central images
courtesy of Dave Alexander.
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