EMD SW1500 Cows & Calfs
Here we are at the last first generation locomotives released by Atlas. Some may argue they are really the beginning of the second generation of motive power because of the release date and the numbering series but I feel, because they were manufactured by Rivarossi using their same basic motor, they belong with the first generation. As with the 0-4-0, the actual release date is a little fuzzy. Model Railroader stated, in the June 1970 issue "New Products" section, they "should be available at your hobby shop as you read this." However, it wasn't until March 1971 that Atlas was advertising them as "New for '71." I guess early 1971 would be about as close as one could get to pinpointing a date.
These were the last locomotives Rivarossi would ever make for Atlas and Atlas would turn to Roco exclusively for what would be the second generation of motive power. Different versions of the Cow and Calf have been available through the years from other importers. Con-Cor released the same Rivarossi version after Atlas discontinued them and then a version using the Rivarossi shell but with a Kato mechanism. There was a re-release in 1997 just before Life-Like released their SW9/1200 series but with a new Chinese mechanism. Rivarossi/Arnold sold them after this but with an unknown, to me, mechanism.
And, guess what? Through all these years there is one thing about the shell never corrected; the cab roof. It should be a smooth, rounded shape as on other SW switchers instead of three flat panels with the middle one being parallel to the ground and the other two sloping away. What happened was Rivarossi used a tentative drawing for a proposed SW1500 when they were working up the shell and EMD ended up releasing the SW1500 with a totally new body design. Hence there is a discrepancy in the designation of these units. Atlas advertised them as SW1500s but they are really a representation of the SW1200 (except for the roof, of course). In fact, the GM demonstrator version had TR12 imprinted on the sides which was EMD's designation for the SW1200.
Speaking of the prototype, the SW1200 was made for many years (1954-1966) and there were over a thousand built, making it one of EMD's most popular switchers. It is almost identical to the earlier SW7 and SW9 models, the only real spotting differences being louver placement and number. All three were 1200 horsepower units. Atlas offered them in Santa Fe, GM Demonstrator, Penn Central, Union Pacific, and Burlington roadnames and all of the railroads represented had SW1200s.
The Rivarossi model is a plastic shell and separate walkway molding over a zamac frame. There is an additional weight that fits into the cab portion of the shell. The same basic Rivarossi motor is used as in their other A1G locomotives but in a quite different configuration. In this case, the motor has a double-ended shaft with a worm on each end. Due to considerable space limitations in this small chassis, the worm diameters are much smaller than on the other Rivarossi A1G locos. The motor is kind of suspended under the zamac frame in an opening in the center with a spring sheet metal retainer that passes through holes in the top of the frame and snaps over the bushing extensions on the motor can and cap. The worms on the shaft then extend into openings in the bottom of the frame. The trucks are retained by plates mounted on the frame at each end with slots in them to engage bosses which extend from each side of the truck gearboxes. The left side plate at each end is insulated from the frame with a plastic spacer between it and the frame. A single screw through both plates and the frame hold them in place with an insulating washer on the left side.Wheel wipers are mounted on the gearboxes in the boss area and make contact with both the inner surface of each wheel and the retainer plates which gets current that far. Wires soldered to lugs under the left plate mounting screws carry current to the motor brush holder on the left (hot) side and the right (ground) brush holder has a flat spring which contacts the motor can and the can is grounded through the motor retainer. Because the right side truck retainer plates are also grounded to the frame, this completes the circuit. Actually, the wiring from the left side of the frame could go to either the right or left side of the motor depending on how the motor cap was installed in the factory since this would determine on which side the ground contact would be. In a departure from the past Rivarossi engines, there are no plastic traction tires used on this locomotive, Thus all eight wheels contribute to current collection with some sacrifice in pulling capacity. This little loco will still pull about 20 cars on level track!
Another couple of notes of interest: This is one of very few early N scale locomotives with the couplers mounted on the frame instead of the trucks (standard Rapido couplers, of course!). There are snap-in retainers to hold the couplers and springs in place. The headlight bulb is actually mounted at the rear of the frame in a plastic socket that fits between the two rear truck retainer plates and plastic pieces in the shell transmit the light to the front of the engine to the headlight. Kind of like fiber optics! The rear headlight is lit too. No directional lights here!
In spite of this locomotive design being eclipsed by later mechanisms, it was rather innovative for the time. Getting that motor and the rest of the drive into a chassis this small was undoubtedly a challenge.
Atlas identification: "ATLAS" and "MADE IN ITALY" on the left bottom of the front truck and right bottom of the rear truck along with the later "RR" block style Rivarossi logo in the middle of the bottom of each truck. "MADE IN ITALY" at the top left of the roof underside of the body and the later "RR" block style logo and a very small "RIVAROSSI" under that at the top right of the roof underside of the body. "RIVAROSSI" and the number 12505 on the left underside of the walkway front and rear respectively. "Made in Italy" on the front right underside of the walkway.
Variations: As far as I know, there are no variations in these locos. Any help would be greatly appreciated.
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:
The images of the Union Pacific Cow & Calf were kindly provided by Mark Peterson from his great Locomotive Encyclopedia site: http://www.visi.com/~spookshow/locos.html
The Burlington Cow image courtesy of Dave Alexander.
The GM Demo Cow and Calf images and the Santa Fe Calf image courtesy
of Jim Starbuck.
|Powered Cow Units:||Dummy calf Units:|
|#4001 Santa Fe||Road #2418||#4011 Santa Fe|
|#4002 GM Demo||"GM" (cab sides) "TR12" (front sides)||#4012 GM Demo|
|#4003 Penn Central||#4013 Penn Central|
|#4004 Union Pacific||Road #DS1870||#4014 Union Pacific|
|#4005 Burlington||Road #9280||#4015 Burlington|
Pick a page to go to:
|EMD E8s||FM C-Liners||IHB 0-8-0s|
|Alco RSC-2s||EMD GP40s||USRA Pacifics (4-6-2s)|
|Plymouth WDT Diesels||0-6-0 Steam Locos||EMD SD45s|
|USRA Mikados (2-8-2s)||0-4-0 Locos and Tenders||Atlas Model Specific Issues|
|Atlas Locomotive Disassembly||The Rivarossi Motor||The Mehanotehnika Motor|
|Zamac Frame Repair||Atlas Locomotive Reassembly||AIG Locomotives Around the World|
|The Treble-O-Lectric Main Page||Treble-O-Lectric Locomotive Service||Treble-O-Lectric Documents|
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