The Dash 8-40BW, or B40-8W, is a four-axle diesel locomotive built by GE Transportation Systems for the Atchison, Topeka and Santa Fe Railway (ATSF) in the early 1990s. It is part of the GE Dash 8 Series of freight locomotives.
|GE Dash 8-40BW|
| • AAR||B-B|
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|Wheel diameter||40 in (1.016 m)|
|Wheelbase||9 ft 0 in (2.74 m)|
|Length||66 ft 4 in (20.22 m)|
|Width||10 ft 1.5 in (3.09 m)|
|Height||15 ft 4.5 in (4.69 m)|
|Loco weight||280,000 lb (127,006 kg)|
|Maximum speed||70 mph (113 km/h)|
|Power output||4,000 hp (3,000 kW)|
|Tractive effort||68,000 lb (30,844 kg)|
The locomotive model designation is interpreted as follows: B (B type truck arrangement, 2 axles per truck) 40 (4000 horsepower) -8 (the generation when it was designed, in this case meaning the late 1980s) W (Widecab).
ATSF was the only railroad to order the B40-8W, and a B unit (cabless booster unit) was almost made with it, but because the price would have been the same for B40-8Ws with cabs or without, they decided to order units with cabs only.
All of ATSF's B40-8Ws became part of BNSF Railway, and many of them were repainted into BNSF's "Heritage 2" paint scheme, although several units still retain their "Warbonnet" paint scheme from their previous careers with ATSF.
While originally built for high-speed intermodal service, by the mid-2000s the B40-8Ws had been bumped to local service.
In mid-2010, BNSF put 15 B40-8Ws up for sale. These units were on long-term lease and were returned to their lessor. Four units have been sold to the Providence and Worcester Railroad in Massachusetts. The PW sold one of their B40-8Ws to the Arkansas-Oklahoma Railroad. The rest of BNSF's B40-8W fleet is, as of 2019, undergoing rebuild and refreshment at GE as preparation for their new role as local freight units.