MPI MP8AC-3
{{Use mdy dates|date=May 2024}}
{{Infobox locomotive
| name = MPI MP8AC-3
R156 (New York City Subway)
| powertype = Diesel-electric
| image = Bway Junction td (2019-01-16) 01 - BMT Jamaica.jpg
| alt = OL919 powers a work train on the BMT Jamaica line
| caption = An R156 locomotive on the BMT Jamaica Line at Broadway Junction station
| builder = MotivePower
| ordernumber = OL912–OL939
| serialnumber =
| buildmodel =
| builddate = 2012–2013
| totalproduction = 28
| aarwheels = B-B
| uicclass = Bo'Bo'
| Britishclass = Bo-Bo
| gauge = {{RailGauge|ussg}}
| trucks = Kawasaki R156 Fabricated Frame
| bogies =
| wheeldiameter =
| trailingdiameter =
| minimumcurve =
| wheelbase = {{convert|36|ft|0|in|abbr=on}}
| length = {{convert|53|ft|3.25|in|abbr=on}}
| width = {{convert|8|ft|8.25|in|abbr=on}}
| height = {{convert|11|ft|5.375|in|abbr=on}}
| axleload = {{convert|29000|lb|t|1|abbr=on}}
| weightondrivers = 100%
| locoweight = {{convert|116000|lb|t|1|abbr=on}}
| fueltype = Diesel fuel
| fuelcap = {{convert|500|USgal|abbr=on}}
| consumption =
| watercons =
| primemover = Cummins QSK 23G
| rpmrange = 600-2100
| enginetype = Inline-6 Cylinder, four stroke cycle diesel engine
| generator = Hitzinger SGS7
| tractionmotors = Siemens SITRAC AC propulsion
{{convert|221|hp|kW|0|abbr=on}} per axle
| headendpower =
| cylindercount = 6
| cylindersize = {{convert|3.8583|L|usgal impgal|abbr=on}}
| transmission = AC-DC-AC
| maxspeed = {{convert|30|mph|km/h|0|abbr=on}}
| poweroutput = Gross: {{convert|860|hp|kW|0|abbr=on}}
Traction: ~{{convert|300|hp|kW|0|abbr=on}} @ {{convert|15|mph|km/h|0|abbr=on}}
| tractiveeffort = {{convert|20250|lbf|kN|abbr=on}} Starting
{{convert|15000|lbf|kN|abbr=on}} @ {{convert|7|mph|km/h|0|abbr=on}}
{{convert|7500|lbf|kN|abbr=on}} @ {{convert|15|mph|km/h|0|abbr=on}}
{{convert|4200|lbf|kN|abbr=on}} @ {{convert|25|mph|km/h|0|abbr=on}}
| trainheating = John Deere 5030HF285, 3.0L, {{convert|96|hp|kW|0|abbr=on}}
| locobrakes = Electro-pneumatic
| locobrakeforce =
| trainbrakes = Pneumatic
| operator = New York City Subway
| operatorclass = R156
| powerclass =
| numinclass = 28
| officialname =
| nicknames =
| deliverydate = 2012–2013
| firstrundate = May 1, 2012
| retiredate =
| disposition =
| notes ={{cite news | url=http://www.railwaygazette.com/news/single-view/view/diesel-locomotives-delivered-to-new-york-subway.html | title=Diesel locomotives delivered to New York subway | work=Railway Gazette | date=July 5, 2012}}[https://www.wabtec.com/uploads/outlinedrawings/MotivePower8AC-Metro-Work-Locomotive.pdf MP8AC-3 Spec Sheet]
}}
The MPI MP8AC-3 is a lightweight diesel-electric locomotive built by the MotivePower division of Wabtec. It was designed from scratch as a work train engine for the New York City Subway system, where it is designated the R156.
Description
The R156 is designed to navigate the clearances and tight turns of the NYC Subway, with weight constrained to {{convert|112000|lb}}, 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. Instead, the R156 is powered by a 6-cylinder, 800 horsepower Cummins QSK 23 diesel engine.{{cite web | url=http://cumminsengines.com/assets/pdf/4087016.pdf | title=QSK-23 brochure | work=Cummins}} A separate, smaller John Deere Diesel drives a generator to provide auxiliary power and to heat the main engine and keep batteries charged when the main engine is not running. Trucks are supplied by Kawasaki, which provides the same wheel and traction sets for the R160 subway cars. The traction motors are Siemens' SITRAC AC motors (the same ones on R160Bs 8843–9102). The R156 locomotives have provisions for the future installation of communications-based train control (CBTC) equipment, which were expected to be installed by June 2017.{{Cite web|url=http://web.mta.info/news/pdf/MTA%202017%20Final%20Proposed%20Budget%20November%20Financial%20Plan%202017-2020%20Volume%202.pdf|title=MTA 2017 Final Proposed Budget November Financial Plan 2017 – 2020 Volume 2 November 2016|date=November 16, 2016|website=mta.info|publisher=Metropolitan Transportation Authority|access-date=November 17, 2016}}
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.{{cite web | url=http://www.mta.info/news/2012/05/02/mta-new-york-city-transit-takes-delivery-new-diesel-electric-locomotive | title=MTA New York City Transit Takes Delivery of New Diesel-Electric Locomotive | work=MTA | date=May 1, 2012 | access-date=1 October 2014}}
References
{{commons category-inline|MPI MP8AC-3 locomotives}}
{{reflist}}
{{MPI Locomotives}}
{{NYCS rolling stock}}
Category:Diesel–electric locomotives of the United States
Category:EPA Tier 3-compliant locomotives of the United States