EMD MP15DC

EMD MP15DC

Mosaic 212, an EMD MP15DC --Brewster, Florida.

Type and origin Power type Diesel-electric Builder Electro-Motive Division (EMD) Build date February 1974–November 1980 Total produced 351

Specifications AAR wheel arr. B-B Gauge 4 ft 8 1⁄2 in (1,435 mm) Trucks 9 ft 0 in (2.743 m) Wheel diameter 40 in (1,016 mm) Length 47 ft 8 in (14.53 m) Width 10 ft 0 3⁄4 in (3.067 m) Height 15 ft 0 in (4.57 m) Loco weight 248,000 lb (112,000 kg) Fuel capacity 1,100–1,400 US gal (4,200–5,300 l; 920–1,170 imp gal) Prime mover EMD 12-645E Engine type V12 diesel Aspiration Roots-type supercharger Displacement 645 cu in (10.57 L) / cyl 7,740 cu in (126.8 L) Generator D32 Traction motors 4 × D77/78 DC Cylinders 12 Cylinder size 9 in × 10 in (229 mm × 254 mm)

Performance figures Power output 1,500 hp (1,100 kW)

The EMD MP15DC was a 1,500 hp (1,100 kW) switcher-type diesel locomotive model produced by General Motors' Electro-Motive Division between March 1974 and January 1983. 351 examples were built. An MP15AC variant, with an AC drive, was also offered. Between August 1975 and August 1984 246 MP15ACs were built, including 25 for export to Mexico, and four built in Canada. The MP15DC replaced the SW1500 in EMD's catalog, and is superficially very similar to the predecessor model, using the same engine (a V12 EMD 645-series powerplant) in a similar design of hood and bodywork. The primary difference is the MP15’s standard Blomberg B trucks.

Switchers up to the SW1500 had been restricted to AAR type A switcher or Flexicoil lightweight trucks, both with a 96 in (2,438 mm) wheelbase. In 1973 60 special order Mexico-only SW1504s were built on a slightly longer frame, allowing EMD’s standard Blomberg B trucks, with a 108 in (2,743 mm) wheelbase, to be used. In EMD's eyes (among others) this made the new locomotive a road switcher rather than a pure switcher, since it was capable of transition and road speeds up to 60 mph (97 km/h) or so. The new model MP15DC designation thus meant Multi-Purpose locomotive, 1500 hp, DC generator. Originally the locomotive was simply designated the MP15; the arrival of the alternator/rectifier MP15AC in 1975 changed the name.

With the success of the MP15, there was a demand for a model with an advanced AC drive system. The MP15AC replaced the MP15DC’s DC generator with an alternator producing AC power which is converted to DC for the traction motors with a silicon rectifier. The MP15AC is 1.5 ft (457 mm) longer than an MP15DC, the extra space being needed for the rectifier equipment. The alternator-rectifier combination is more reliable than a generator, and this equipment became the standard for new diesel-electric locomotive designs.