MPI MP8AC-3 R156 (New York City Subway)
An R156 locomotive on theBMT Jamaica Line atBroadway Junction station
Type and origin Power type Diesel-electric Builder MotivePower Order number OL912–OL939 Build date 2012–2013 Total produced 28
Specifications Configuration: ​  • AAR B-B  • UIC Bo'Bo'  • Commonwealth Bo-Bo Gauge 4 ft 8+1⁄2 in (1,435 mm) Trucks Kawasaki R156 Fabricated Frame Wheelbase 36 ft 0 in (10.97 m) Length 53 ft 3.25 in (16.2370 m) Width 8 ft 8.25 in (2.6480 m) Height 11 ft 5.375 in (3.48933 m) Axle load 29,000 lb (13.2 t) Adhesive weight 100% Loco weight 116,000 lb (52.6 t) Fuel type Diesel fuel Fuel capacity 500 US gal (1,900 L; 420 imp gal) Prime mover Cummins QSK 23G RPM range 600-2100 Engine type Inline-6 Cylinder,four stroke cyclediesel engine Generator Hitzinger SGS7 Traction motors Siemens SITRAC AC propulsion 221 hp (165 kW) per axle Cylinders 6 Cylinder size 3.8583 L (1.0193 US gal; 0.8487 imp gal) Transmission AC-DC-AC Train heating John Deere 5030HF285, 3.0L, 96 hp (72 kW) Loco brake Electro-pneumatic Train brakes Pneumatic
Performance figures Maximum speed 30 mph (48 km/h) Power output Gross: 860 hp (641 kW) Traction: ~300 hp (224 kW) @ 15 mph (24 km/h) Tractive effort 20,250 lbf (90.1 kN) Starting 15,000 lbf (67 kN) @ 7 mph (11 km/h) 7,500 lbf (33 kN) @ 15 mph (24 km/h) 4,200 lbf (19 kN) @ 25 mph (40 km/h)
Career Operators New York City Subway Class R156 Number in class 28 Delivered 2012–2013 First run May 1, 2012
[1][2]

TheMPI MP8AC-3 is a lightweightdiesel-electric locomotive built by theMotivePower division ofWabtec. It was designed from scratch as awork train engine for theNew York City Subway system, where it is designated theR156.

The R156 is designed to navigate the clearances and tight turns of the NYC Subway, with weight constrained to 112,000 pounds (51,000 kg), so it can operate on elevated portions of the system. It joins a fleet of 62 diesel-electric work locomotives on the system.Third rail power is not used because the third rail is normally turned off at work sites for safety reasons.^[3] Instead, the R156 is powered by a 6-cylinder, 800 horsepowerCummins QSK 23 diesel engine.^[4] A separate, smallerJohn Deere Diesel drives a generator to provideauxiliary power and to heat the main engine and keep batteries charged when the main engine is not running. Trucks are supplied byKawasaki, which provides the same wheel and traction sets for theR160 subway cars. The traction motors areSiemens' SITRAC AC motors (the same ones on R160Bs 8843–9102). The R156 locomotives have provisions for the future installation ofcommunications-based train control (CBTC) equipment, which were expected to be installed by June 2017.^[5]

The MTA ordered 28 units in 2006. After some difficulty with the initial prototype, the first unit, numbered OL912, was delivered on May 1, 2012.^[3]

Media related toMPI MP8AC-3 locomotives at Wikimedia Commons

• MPI locomotives
• New York City Subway
• Diesel–electric locomotives of the United States
• EPA Tier 3-compliant locomotives of the United States
• Standard-gauge locomotives of the United States
• Railway locomotives introduced in 2012

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