The GE, General Electric, C40-8 (Dash 8-40C, C40-8C, or simply Dash 8) is a type of six-axle, 4,000hp diesel locomotive built from 1987 to 1992 with exactly 586 built; including over 800 C40-8W units, having about 1,600 total.
The C40-8 is the 6-axle counterpart of the B40-8 (its four-axle counter-part), as well as being the first official member of GE's Dash 8 Series to be a 4,000` hp locomotive.
Many are still in service on US and North American Class 1 railroads, with some railroads currently having portions of their C40-8 rosters in storage (most notably Norfolk Southern and Union Pacific), aside from units in the process of being retired. CN, however continues to purachase used GE Dash 8's from UP and BNSF.
The GE C40-8 is considered to be one of the most revolutionary diesel locomotives produced by GE, because of it being the very first six-axle DC-traction diesel locomotive to have 4,000hp, as well as having modern, high-tech microprocessor controls, and including an American Safety Cab (or wide-cab) variant; the C40-8W (or C40-8CW), which provided better safety for head-on collisions and crew visibility (besides improved microprocessor technology).
Railroads such as the Chicago And Northwestern (CNW) and the company that eventually purchased the railroad; Union Pacific, were the two main customers who first purchased the C40-8 to be used on their heavy and fast-paced intermodel service, as well as on coal drag or coal train service. While later companies such as CSX, Conrail and Norfolk Southern purchased units towards the mid-1990's.
CSX purchased their first fleet of Dash 8 units in 1991 and they were painted in an exclusive variant of their "Stealth" scheme known as "Grey Ghost" (nicknamed by railfans and employees), as well as the units having italicized numbering and lettering to help distinguish the once-unusual and highly uncommon 4,000hp type of diesel locomotive model. Yet, CSX's Dash 8 fleet grew from having only 25 to 30 units (later 70 or more) to about 150 before the purchase of Conrail (though, Conrail only had about 24 original C40-8 units with an abundant amount of "W" units) from CSX and NS in 1999, as well as having units leased and eventually purchased acquired from their main competitor (NS) later on (being former Conrail B40-8 units sold to NS and eventually acquired by CSX). Thus, making CSX currently the largest owner for Dash 8 units (though, only half; as mentioned, were part of their original fleet); all which are still currently in use.
Canadian Railroads such as BC and CN eventually grew interested in purchasing a fleet of cowl-bodied, Canadian-built C40-8W units, which were classified as the C40-8M. These units were produced by the Canadian portion of GE, as well as some being built by CN and BC before CN purchased BC in 2004. Such units are in the process of being retired by CN (as of 2011-2013), and are to be replaced with former BNSF and UP C40-8's from CNW and ATSF heritage.
In 2014 NS began a program to rebuild 84 C40-8's it owns into C40-8.5W's.
The C40-8W model itself revolutionized modern diesel locomotives by having a high-horsepowered engine (with a built-in turbocharger) and consisting of having a wide-cab, thus becoming the new standard for average diesel locomotives as opposed to having lower horsepower and a standard cab like with most, or 75% of other types of American and/or North American diesel locomotives built from 1964 to 1985 (excluding Canadian-built diesel locomotives; being wide-cab with cowl cabs or cowl bodies; such as the F40PH, F45, and U30CG having such body and cab style, but not including the DDA40X due to it being the first EMD diesel locomotive to retain a wide-cab, yet it being a "double-diesel" type).
They first grew popularity with Union Pacific and Conrail, but eventually saw interest with CSX.
There are also several versions of the C40-8:
C40-8W (wide-cab/safety-cab; as listed above)
C40-8M (cowl-bodied; as listed above)
C41-8 (experimental 4,135hp upgraded version)
C41-8W (experimental upgraded wide-cab 4,135hp version of the C40-8W)
C44-8W (specially ordered by CSX with 52 examples built; all currently downgraded and de-rated to 4,000hp and classified as "C40-9W or C44-9W" due to having Dash 9 components)
C40-8.5W - NS Juniata has begun rebuilding C40-8 units with wide cabs.
Because of how different the cab for the C40-8W is, the controls are placed differently like with other wide-cab GE units. The C40-8 was proven to be able to replace 5 SD40-2 units on an average mainline freight train with only needing 3 or 4 units as opposed to 5; aside from the fact that they originally wanted, advertised, or demonstrated to the Burlington Northern who once had one of the largest fleets of SD40-2's and were their main locomotive.
UP #9400 was the 1,000th Dash 8 unit built in 1993, and is currently in storage as of 2012.
UP #9405 was also dedicated to having a safety record by having a special plaque applied to the side of the cab similar to UP 9700.
GE Evolution Series locomotives are more capable of replacing 3,200hp locomotives such as the SD40-2 as opposed to the C40-8. Hence, two ES44AC units can replace 5 SD40-2's; aside from 2 AC4400CW units replacing 5 SD40-2's as well.
The CNW's final three C40-8's that were ordered were experimental upgraded 4,135hp units, which weren't very successful, and proved to be unnecessary due to the introduction of the C44-9W (Dash 9) the following year in 1993.
Conrail originally "over-ordered" a fleet of C40-8W units (with them having over or at least 215 units), to which they were no longer necessary, or were rarely used. Hence, the company sold a fleet of 60 units to LMX (or LMSX leasing) which were eventually purchased by the Illinois Central (IC) shortly before becoming purchased by the CN, as well as CSX and NS purchasing several units before the Conrail split in 1999.
Only two former "Grey Ghost" YN1-painted or patched CSX C40-8's are still left on their roster. The rest are painted in YN2 and YN3 paint.
The C41-8W originally had its own unique type of trucks, which were often used on several C40-8C's.
Union Pacific is also in the process of retiring their fleet of C40-8's, to whom they've been leased and sold to Norfolk Southern and CN, as well as various different leasing companies such as HLCX, CEFX, NREX and LLPX having several former UP C40-8's.
Most of CSX's former Conrail Dash 8's still have their original marker lights.
CN 2122 (formally UP 9087 and originally CNW 8575) is actually one of the three former CNW C41-8C units which survived as being one of the only CNW-painted Dash 8 units on UP's roster before becoming one of the many former UP Dash 8's purchased by CN. (The unit was also one of the only unpatched CNW Dash 8 units before eventually receiving patchwork in 2005-2006.) The unit has since been converted since CN's purchase.
The C44-8W originally had a few minor differences between every other variant of the C40-8W; the most notable difference being the frame steps.
NS #8305 (one of the last former Conrail-painted C40-8 units on the railroad's roster) is in the process of undergoing an overhaul to be rebuilt with a "Crescent Cab" as with NS' fleet of SD60E units. NS currently classifies their C40-8 rebuilt units as the "C40-8.5", "C40-8E", or the "C40-8WE". NS #8311 is scheduled for overhauling as well.
The CREX Leasing Corp. (as with NREX and numerous other leasing companies) has several fleets of former UP C40-8 units; most which originate from CNW ancestry.
Conrail briefly experimented with using DPU technology on their C40-8W units around 1995-1996, yet the experiment was unsuccessful.
CN #2113 (a former UP nee CNW C40-8) was painted with a special banner commemorating the CN's 15th anniversary of independence from the Canadian government in 2010.