The EMD (Electro Motive Division) SD70M is a type of 4,000hp six-axle diesel locomotive built from 1992 to 2004 (and briefly resumed from 2005 to 2007-2008) with over 1,600 built.
EMD SD70M Demo

EMDX #7000: one of the first SD70M units built and demonstrated upon introduction.

It is practically the modified or wide-cab version of the original SD70 (the "M" meaning, "modified"), only with minor external and internal differences (such as having a desktop-style control stand rather than the usual conventional form).

Union Pacific (UP), Santa Fe (ATSF), Southern Pacific (SP), and Canadian National (CN) were the original customers to purchase the SD70M (including its counter-parts), while Ontario Northland Railway (ONR), Norfolk Southern (NS), and the NYSW (New York And Susquehanna Railway), and several Latin American railways and railroads were the later customers, for the SD70M was still available for export despite having been replaced by the SD70M-2 in 2004-2005.

Many still exist in active general revenue service and have been purchased by various different railroads, with Union Pacific having the largest fleet (having exactly 1,454; including the 25 ex-SP units in which they acquired during the 1996 merger). Though, some have been wrecked, rebuilt, and/or retired. Some are also currently placed in storage, and are used as spare units along with a handful of Dash 9 units (notably with UP and BNSF).


After the initial success of the original SD70's introduction (despite popularity issues), EMD planned on developing an improvised type of "safety cab" for the FRA's "North American Safety Cab" program, which consisted of having a better design for more comfort and easier maintenance access for train crews and mechanics as well as providing safer durability during head-on collisions. The cab was furthermore an evolution from their earlier, less-successful and otherwise flawed cab designs used on their GP60M and "Phase 1" SD60M units. Thus, the EMD SD70M was born (aside from it's more successful and popular AC-traction "brother"; the SD70MAC, prior to the SD70M's introduction) to earn more popularity among the FRA and potential customers whom previously sought no interest in the original SD70 model.

Despite having been somewhat successful at first, the model began to experience several technical issues with its microprocessor control system along with numerous electrical issues involving the cab during early demonstrations. Furthermore, the problems hindered the model, and sparked more interest from rival GE to develop their increasingly-popular C44-9W a year later. To make matters worse, only two customers ordered the model in very small numbers: SP with twenty-six and NYSW with three, in addition to the three demonstrator units and 22 EMDX lease units. The model's horsepower rating was also merely a fad that had already passed with preceding models like the SD60 and C40-8, and the 4,400hp C44-9W was already picking up in greater numbers by railroads and further prompted the so-called "horsepower race" of the 1990's between the two locomotive builders. Another factor was with EMD's increasingly-popular AC-traction SD70MAC (the SD70M's counter-part), which sold in much larger numbers (by the hundreds) in contrast to the SD70M (having roughly 33 at the time of the model's debut). But after several successful demonstrations with the ATSF, they became an instant customer and placed orders on a relatively large fleet of specialty SD70M units known as the SD75M: ATSF's exclusive 4,300hp (and 4,125hp in some cases) version of the locomotive, which helped boost sales and popularity dramatically, further prompting Union Pacific to do the same. 

In an effort to replace their vast armada of aging SD40-2 units in 1999, Union Pacific placed an order for a total of over 1,300 SD70M units, making it the largest single-model locomotive order ever placed in North America; despite not receiving deliveries until early 2000. Numerous production changes also became underway from 2001-onwards following the first deliveries. Such changes involved having distinct flared radiators (due to the implementation of the US EPA's "Tier 1" policy for the following year) with an updated cooling system divided into independently controlled sections (engine jacket water is handled by one part of the radiators; water for the after coolers is managed by another). Other changes included updated software technology for the locomotive's microprocessor control system, which furthermore included the ability to provide Controlled Tractive Effort (CTE); which helps provide a much more smoother (yet with reduced traction) performance when hauling a long and heavy train, along with controlling the power distribution when assigned or "mated" with a DPU (Distributed Power Unit) on the rear or middle of a train. Said units are known as the SD70M "Phase 2", though most earlier units just consisted or contained one feature as opposed to the other (such as one unit having only flared radiators, the other having only updated software, etc.). The first "Phase 2" units were UP 4635-4639 built in December 2000, and were pre-production testbeds built in London, Ontario, Canada. The units built after (#4640-4709) were included with updated software, while #4710-4836, #5103-5126, and #4850-5126 are production "Phase 2" units built with flared radiators and additional upgraded software.

Many of the later production SD70M units ordered by UP (specifically UP 4119-4164) were assembled at Super Steel Schenectady Inc. in Glenville, NY and painted by Alstom at Hornell, NY as a result of increasing demands and limited workloads at London, Ont.; meaning that the rather small facility was unable to fulfill multiple orders placed by UP simultaneously, and requested independent contractors to finish the orders to meet customer satisfaction (by completing and delivering the units on-time). Other units were also assembled and completed at Bombardier's Concarril, Sahagún, Mexico contract facility. By the time the last unit was completed in 2003, UP amassed a total of 1,454 SD70M's (of the 1,646 built domestically or for domestic customers) which included the 25 ex-SP units inherited through the merger as well as the 1,429 units delivered over the course of a three-year time-span. Concurrently to the 1996 SP merger, UP grew interested in placing the massive order while the 25 SD70M units were initially placed and evaluated alongside the EMDX demonstrator units in general revenue service years prior to the placement of the order in 1999. Furthermore, the successful reports that crews gave to locomotive managers sparked interest.

Although not commercially successful at first, the SD70M eventually became a well-received model by a select few amount of customers later-on in production. Despite not being as favorable as its AC-traction counter-part, the model was still a success and sold in a fairly large number compared to its predecessor: the SD60M.


UP 4837 SD70M

UP #4837 was the first "Phase 3" SD70M built in November 2002.

The SD70I (the "I" meaning, "isolated", or "improved" in some instances) was Canadian National's "whisper cab" version of the SD70M, which contains a separate piece of insulation to reduce engine noise and cab vibrations. Yet, the name "SD70I" is no longer used to describe their original "whisper cab" production SD70I units because of the upgraded, higher-horsepower SD75I being the replacement for the 26 units built. In other words, CN's original exclusive fleet of DC-traction SD70I units were converted into SD75I units, or upgraded to SD75I specs, but still retain their original features and numbers. Thus, the name is now used as an alternate name for Union Pacific, CSX, and Norfolk Southern's fleets of "Phase 2" and "Phase 3" SD70M and SD70MAC units which consist of flared radiators (meaning that they have an improved cooling system), redesigned full-height doorway cabs, and more advanced microprocessor control systems. The SD75I name is mainly used to describe CN's version of the SD75M and converted SD70I units, but is also used for classifying the Latin American variant, the 6 units ordered by ONR (Ontario Northland), and the 26 SD75I units received during the BNSF merger in 1995-1996 as well. Despite the SD70I and SD75I being the only isolated cab locomotive models built with such model designation, they are not the only one's built with such cab distinction or feature, for the SD90MAC, SD70ACe, and SD70M-2 were also built with isolated cab variants but didn't receive a notable distinction.
CSX 4731

A brand-new CSX SD70AC (otherwise known as an "SD70AH", SD70MAC "Phase 2", "SD70I", or SD70MAC 'Phase 3") in 2003. The model variant is similar to a "Phase 2" SD70M due to having flared radiators. An isolated cab noted by the visible seam on the nose is also present, thus further denoting the "I" designation in some cases. Other features include thick metal plating beneath the frame for additional weight sustainability similar to the road's GE "ES44AH" specialty variant of the original ES44AC, for the model was built to the road's specifications regarding coal drag applications.

Flared-radiator SD70M units are also known simply as the SD70M "Phase 2"; as opposed to SD70M-2 (said radiator section is flared to comply with the US EPA's "Tier +1" emissions act). Though, to avoid confusion between the original SD70MAC and it's flared-radiator counter-part (which is mechanically different compared to it's DC-traction counter-part), CSX simply classified their special "Phase 2" SD70MAC units ordered in 2003 as the "SD70AC" because of having different features from its predecessor, and to further avoid confusion with existing "Phase 2" SD70M units.

Later on when EMD briefly resumed production from 2005 to 2007, SD70M units ordered by foreign railways in Latin America received the distinct notched cab, as well as having all the additional features offered with the previous version of the model rather than simply having one or the other. Thus, being dubbed as an SD70M "Phase 3" (and in some cases, SD70I "Phase 2"). Said units mentioned are also considered to be known simply as an "SD70I" to differentiate between their domestic counter-parts.


Responding to the 4,400hp rating of the increasingly popular C44-9W from GE, EMD bumped the output of the 16-710G3B engine from 4,000 to 4,300hp and the 16-710G3C-equipped SD75 was born. ATSF (Santa Fe), CN (Canadian National), and ONR (Ontario Northland Railway) were the only customers to order both variants of the model: the wide-cab SD75M and the "isolated cab" SD75I. Both were built between 1995 to 1999, spawning a total of 283; a merely small number compared to the vast amount of Dash 9's built from 1993 to 2004.

A total of 76 SD75M's were built from 1995 to 1996. 51 were received by the ATSF, while an additional amount of 25 were delivered during the BNSF merger process and retained their original "Warbonnet" liveries; minus having been patched with BNSF decals (similar to the BN's SD70MAC fleet along with ATSF/BNSF's Dash 9's).

A typical CN SD75I hauling a manifest train with a C44-9W.

Said units were meant to be placed in immediate service following a brief power shortage, and were hastily given simple patchwork decals due to the newly-established company having a non-existent paintscheme at the time. 26 SD75I's were received during the BNSF merger as well. Upon the BNSF merger in 1996, the vast fleets of ex-ATSF SD75M diesels also received a simple renumbering into the newly-established "8200" series rather than being part of the original "200" series.

As for CN, a total of 175 SD75I units were ordered and delivered from 1997 to 1999. The last 35 units ordered were assembled in 1999 at Alstom's Montreal, Quebec facility in the former CN Pointe St. Charles shops. Simultaneously, ONR's fleet of six units were built and assembled to CN specifications, and delivered prior to the completion of the last CN unit. Although neither model sold well, sales figures for the SD75I were greater thanks to CN. Furthermore, both models were generally specialty units built to the customer's specifications.

During 2013 on into mid-2014, BNSF has retired the vast majority of their fleets of former ATSF (Santa Fe) SD75M units in favor of making way for ordering more EMD SD70ACe units and GE ES44C4's: there more preferred choice for motive power. As of late-2014, NS has been acquiring fleets of ex-ATSF/BNSF SD75M and SD75I units and plans to rebuild and convert said units as part of their current rebuilding program which took effect in 2011.

Many of the remaining, non-retired, or auctioned SD75M and SD75I units currently owned by BNSF have been renumbered and currently are assigned to local, yard, and spare duties. Ironically, the remaining ex-ATSF SD75M's have received their original, previous numbers while those which never retained said number eventually received them; notably with the SD75I units. In other words, units like BNSF 8282 became BNSF 282.

The only external distinction between the two models, is that the SD75I has a seam at the front of the nose or hood, indicating its prominent "isolated cab" feature, which can also be found on many later models such as the "Phase 2" and "Phase 3" SD70MAC units built to CSX, TFM, and BNSF specifications (besides having Tier +1-compliant flared radiators complimentary of the US EPA's regulations). Furthermore, the nose of the cab is constructed as two pieces rather than a single piece, and is supported by thick rubber lining that dampens vibrations and cuts down the noise levels because of it not being directly attached to the frame of the unit. Why the cab was developed, was a result of complaints from train crews whom had a very uncomfortable ride with earlier variants or units of the SD70M or SD75M prior to the debut of the subsequent SD70I/SD75I models. Like Conrail's SD60I, these units were well-received and became generally favorable amongst crews and other employees.


  • The main ways of distinguishing an SD70M from its other counter-parts, is by the length, radiators,
    EMD SD70I

    A diagram example showing the features and revealing the differences between the later "Phase 2" SD70M versus the original SD70M.

    and the absence of a more distinct blower duct for the traction motors.
  • The SD70MAC has an SD60-style blower duct, but has an SD70M's carbody while the SD75M and its Canadian "whisper-cab" counter-part are slightly longer than the original SD70M as well as the SD70MAC.
  • "Phase 3" SD70M units have their own distinct, unique notched cabs; notably on the front hood or "nose". They were built with such features to accomodate clearances with train crews.
  • Left-side vent or air intake screen used for rear traction motors located below the rear hood radiator section.
  • SD75I and SD75M units have distinct beveled outcropping bulges located on both sides near the central air intakes where the traction motor blower duct is usually found on earlier EMD models like the SD40-2, whereas SD70M units have a single-sided outcropping which favors the earlier models more well.


Model SD70 SD70I SD70M
Production Dates 1993-1999 1992-2004 1995
Total Built 122 26 1646+*
Length 72' 4" 72' 4" 72' 4"
Wheel Arrangement C-C C-C C-C
Engine 16-710G3B 16-710G3B 16-710G3B
Horsepower 4,000 4,000 4,000
Traction Motors D90TR D90TR D90TR
Alternator AR20 AR20 AR20
Weight x 1,000lbs. 394 398 390-400

Note*: SD70M replaced in domestic catalog by Tier 2-compliant SD70M-2. Model was available for export sale from 2005 to 2007-2008.

Model SD75M SD75I
Production Dates 1995-1996 1996-1999
Total Built 76 207
Length 72' 4" 72' 4"
Wheel Arrangement C-C C-C
Engine 16-710G3C 16-710G3C
Horsepower 4,300 4,300
Alternator AR20 AR20
Traction Motors D90TR D90TR
Weight x 1,000lbs. 394,000 394,000

Note*: Only 173 SD75I units currently remain in service as a result of a wreck destroying two units.

Production Roster (SD70M)Edit

Owner Road Numbers Quantity Date Built
EMD (Electro-Motive Demo) [1] 7000-7002* 3 1992
EMD Leasing (EMDX) [2] 7003-7024* 22 1995
Ferrominera Orinoco (Venezuela) [3] 1052-1057* 6 2002
New York, Susquehanna & Western (NYSW) [4] 4050, 4052, 4054 (even nos.)* 3 1995
Norfolk Southern (NS) [5] 2581-2648* 68 2000-2004
Southern Pacific (SP) [6] 9800-9824* 25 1994
UP (Union Pacific) [7] 3779-3973, 4000-4074, 4089-4999*, 5103-5231 1,310+ 2000-2004*

Notes 1 and 2*: Became CSX 4678-4699, while EMD 7000-7002 became CSX #675-4677.

Note 3*: Ex-UP back-order "Phase 3" SD70M units exported to Venezuela.

Note 4*: Now with NS.

Note 5*: NS 2591-2648 are "Phase 3". All others are "Phase 1".

Note 7*: UP 4635-4639 were preproduction Tier +1 testbeds built in 2000, and are equipped with flared radiators to meet emission requirements.

Note 7*: UP placed order for first SD70M units in October 1999, but didn't receive deliveries until the beginning of the following year.

Note 7*: From 2002 onwards, all SD70M (and subsequent SD70MAC) units were built with flared radiators; UP #4710 was the first to include this feature. UP #4710-4836 are "Phase 2".

Note 7*: UP 4837-4849, 3971-3973, and 5127-5231 are "Phase 3". UP #4837 was the first "Phase 3" SD70M built, and has a "Phase 2" or "Phase 2.5" notched cab.

Production Roster (SD75M)Edit

Owner Road Number(s) Quantity Date Built
ATSF (Atchison, Topeka, and Santa Fe) 200-250 51 1995
BNSF (Burlington Northern Santa Fe) 8251-8275 25 1995-1996

Production Roster (SD75I)Edit


Road Number(s) Quantity Date Built
BNSF (Burlington Northern Santa Fe) 8276-8301 26 1996-1997
CN (Canadian National) 5626-7800 175 1997-1999
Ontario Northland Railway (ONR) 2100-2105 6 1999


Ironically, UP's SD70M fleet is numbered in the same number series as their former 4-6-6-4 "Challenger" articulated steam locomotives. UP 3974-3999 (some being former SP units) are numbered in this order except for #3985; their preserved and operating 'Challenger'.

Despite having an exceptionally large fleet of ex-ATSF SD75M's/post-merger SD75I's, BNSF favors and primarily relies on their vast Dash 9 and GEVO fleets for general revenue service along with utilizing their SD70ACe and SD70MAC units for coal drag service rather than assigning SD75's with Dash 9's or Dash 8's and vice-versa. Thus, explains why BNSF currently is currently retiring their otherwise neglected and unfavorable SD75 units.

SD70I units with their original SD70M carbodies are simply referred to by their original names, similar to how converted GE C44-9CW and AC4400CW units are.

The SD75I (aside from the SD89MAC prototype) also inspired the development for the SD70M-2 and SD70ACe with having 4,300hp, and including more advanced microprocessor control software.

UP #2001 and UP #2002; SD70M units (now SD70I units) were painted in special schemes to commemorate the 2002 Salt Lake City Winter Olympics from 2001 to 2002. These units still retain their special schemes, but are slated to be repainted soon.

The EMD SD70M was also one of the last types of locomotives to be manufactured at EMD's LaGrange, Illinois facility; which no longer primarily manufactures locomotives, but rather rebuilds and distributes various replacement parts for various diesel locomotives of both past and present.

The NYSW was the only US Class 2 or Class 3 railroad to purchase the model.

Since late-2012, CSX has sold the vast majority of their SD70M and SD70MAC units to the Paducah And Louisville (PAL) regional railroad affiliate in Kentucky.

During the BNSF merger in 1995-1996, the railroad experienced a power shortage and required units for immediate service. Thus, the back-order SD75I units originally placed with an order with the ATSF prior to the merger were placed in immediate service and didn't receive decals until after their duties were fulfilled (a similar dilemma was also faced with their back-order Dash 9's and SD70MAC's).

Recently the NYSW retired all three of their SD70M units to be auctioned to NS; despite being less than 20 years old.

In the waning years of the SP, the railroad originally employed all 25 of their SD70M's to its "I-5 Corridor" route for intermodal service between Los Angeles, CA to Portland, OR. All units were acquired by UP in 1996, and were eventually given patchwork before finally receiving the current "wing shield" and "lightning bolt" variants of their "Armor Yellow" livery.

CSX #4685 is the "Spirit of Mulberry", and is one of the numerous "Spirit Of" dedication units from within their roster. CSX #4688" is the "Spirit of Tampa", while #4699 is the "Spirit of Miami".



Big Power Move!! 26 BNSF SD75M's, With 19 Warbonnets!!03:19

Big Power Move!! 26 BNSF SD75M's, With 19 Warbonnets!!

BNSF SD75M fleet being towed to NRE (National Rail Equipment's) Silvis, IL facility for retirement (the consist mostly being ex-ATSF 200 series units).

Must See!! Biggest UP Stacktrain i have ever seen!!! KG1LA-04 Just Massive!!07:12

Must See!! Biggest UP Stacktrain i have ever seen!!! KG1LA-04 Just Massive!!

A long UP intermodal train with an SD70M ("Phase 2" or SD70I) serving as a CTE unit alongside an ES44AC (C45ACCTE) DPU mid-train.

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