EMD Marine Engines: 567, 645, and 710 Series

Electro-Motive Diesel (EMD), today a brand of Progress Rail (a Caterpillar company), builds two-stroke uniflow-scavenged medium-speed diesels in the 567, 645, and 710 series. The number in each name is the per-cylinder displacement in cubic inches. Over 72,500 engines across all three series have been delivered worldwide, and the same basic architecture that powered American railroads for eight decades also drives tugboats, inland towboats, ferries, offshore supply vessels, drilling-rig gensets, and US Navy auxiliary craft.

EMD’s path from a Cleveland railcar startup to a Caterpillar subsidiary spans exactly a century, and the marine chapter of that story is inseparable from the locomotive chapter. The 567 that powered Normandy-bound LSTs in 1944 shared its bore, stroke, and unit-injector system with the freight locomotive running on parallel tracks back home. That parts-community logic is why operators on US inland waterways, Gulf Coast tug fleets, and offshore platforms kept ordering EMD power long after European and Japanese four-stroke competitors had taken most of the global medium-speed market.

For the broader context of US diesel makers, see the marine engine makers directory. The scavenging system that distinguishes EMD’s two-stroke design from loop-scavenged alternatives is covered in uniflow scavenging in two-stroke marine engines and loop scavenging versus uniflow scavenging. For the Detroit Diesel 71 and 92 series, which shared the two-stroke approach but used a different loop-scavenged block, see Detroit Diesel marine 71 and 92 series.

Founding and the General Motors years

Harold L. Hamilton and Paul Turner incorporated the Electro-Motive Engineering Corporation in Cleveland, Ohio on August 31, 1922. The firm started in the gas-electric railcar business, marketing self-propelled railcars that used General Electric traction equipment. General Motors bought both Electro-Motive and the Winton Engine Company in 1930. Winton was then the most advanced American builder of high-speed diesel engines; its two-cycle, V-type diesels had already shown they could run faster and lighter than the heavy marine slow-speeds of the era.

Charles Kettering, GM’s research chief, drove the engineering program from the start. The Winton 201A engine that debuted in 1934 for the Burlington Railroad’s Zephyr established the design platform that all three later engine families would follow: two-stroke, uniflow-scavenged, unit-injected. On January 1, 1941, GM consolidated locomotive work under a single Electro-Motive Division (EMD) with its main assembly facility at LaGrange, Illinois, outside Chicago. Ground for that plant had been broken in March 1935; the first locomotive rolled out on May 20, 1936.

The division of labor matters for understanding where marine engines fit. When EMD was formed in 1941, non-locomotive Winton engine lines, covering marine and stationary power, were separated into GM’s Cleveland Diesel Engine Division (CDED). Cleveland Diesel handled the large non-railroad two-strokes through 1962, when GM dissolved it and merged the product lines back into EMD. From 1962 onward, EMD held responsibility for locomotive, marine, and stationary engines under one roof at LaGrange.

World War II naval production

The Navy needed power for a vast landing-ship program starting in 1942. The chosen vessel was the LST (Landing Ship, Tank), designed to run onto beaches under combat conditions and retract. Naval architects wanted a reliable, proven engine that American industry could produce at scale. They picked the 12-cylinder 567A, which had already logged millions of miles in freight service.

EMD modified the 567A specifically for marine service. The standard locomotive oil sump was redesigned to handle the rolling and pitching motions of a seagoing vessel. The exhaust manifold switched from a dry locomotive design to a water-cooled marine type. Narrower blower drives moved inboard to reduce overall beam. Marquette governors replaced the locomotive units for marine speed control. A two-piece floating piston design, introduced in 1943/1944, replaced the single-piece casting that a wartime foundry couldn’t produce fast enough. The resulting engine was designated the 12-567ATL (the suffix stood for Atlantic Tank Landing, with P or S added for port and starboard rotation to give counter-rotating twin-screw propulsion).

Each 12-567ATL was rated at 900 hp at 744 rpm. Two engines drove one LST through Falk reverse-reduction gearboxes with 2.48:1 ahead and 2.52:1 astern ratios. EMD ran a pre-production prototype on a test stand for 17 continuous days, hitting 960 hp at 720 rpm and then 1,200 hp at 800 rpm before Navy representatives signed off. By the end of the war, EMD had delivered 2,140 engines to the LST and Patrol Craft (PC) programs. Of the 1,052 LST Type II vessels completed, the majority were powered by a pair of 12-567ATL engines; about 117 ships went to Allied navies under Lend-Lease. Additionally, roughly 100 Defense Plant Corporation wartime tugboats received the shorter 8-cylinder 567 variant.

The durability of the 567ATL is not theoretical. USS LST-393, preserved as a moored museum ship in Muskegon, Michigan, still carried its original twin 12-567ATL engines and ran them as recently as 2017. USS LST-325, operated as a traveling museum ship, retains its 567s in running condition.

EMD also built the 16-184A “pancake” diesel for SC-497 class subchasers, a compact V16 producing 1,540 bhp that gave those 110-foot vessels 21-knot speed from twin installations. A separate naval program used the 16-338, rated at 1,090 bhp, in Tang-class submarines, though reliability difficulties eventually led to replacement by Fairbanks-Morse opposed-piston engines in that application.

The 567, 645, and 710 series: bore, stroke, and the displacement-naming convention

The three EMD engine families share a design logic that makes the series number a direct statement of per-cylinder displacement in cubic inches. That naming convention is straightforward to trace across the three generations, and the dimensional relationships between them reveal how much of the architecture carries forward and how little was changed at each step.

567 series: 1938 to 1966

The 567 takes its name from the 567.5 cubic-inch (9.3 L) displacement of each cylinder. Bore is 8.5 inches (216 mm); stroke is 10 inches (254 mm). The engine runs as a two-stroke at a 45-degree V-angle, available in V6, V8, V12, and V16 configurations. All variants use four poppet-type exhaust valves in the cylinder head and either a Roots-type supercharger or a turbocharger for forced induction. Maximum governed speed is 900 rpm; idle sits at 180 rpm.

The 567 series progressed through six variants between 1938 and 1966: 567, 567A (1941), 567B (1946), 567C (1953), 567D (1959), and 567E (1966). Each step brought incremental improvements to combustion, durability, and, from the C onward, optional turbocharging that pushed per-cylinder output well beyond the Roots-blown baseline. The turbocharged 567D and 567E could develop up to 2,500 hp in V16 form, representing roughly 156 hp per cylinder in turbocharged trim versus about 100 hp per cylinder in the original Roots-blown configuration.

Marine 567 engines were always offered in left-hand and right-hand rotating configurations so a twin-screw installation could run counter-rotating propellers from a pair of identical engines, differing only in crankshaft rotation. That feature carried through to the 645 and 710 as well.

645 series: 1965 to the mid-1990s

The 645 replaced the 567 in 1965. The cylinder count and the 45-degree V-angle stayed identical; the defining change was a larger bore that pushed per-cylinder displacement to 645 cubic inches (10.6 L). Bore expanded to 9 1/16 inches (230 mm), a gain of 9/16 inch over the 567; stroke stayed at 10 inches (254 mm). The displacement increase from 567.5 to 645 cubic inches works out to about 14 percent per cylinder. Compression ratio is 14.5:1 on the standard Roots-blown version.

The series ran in V6, V8, V12, V16, and V20 forms. Two induction paths were offered. Roots-blown variants used a mechanically driven supercharger and were simpler to maintain. Turbocharged variants used gear-driven turbochargers with an overrunning clutch that let the unit function as a centrifugal blower at low engine speeds, filling in scavenging air before exhaust energy could spin the turbocharger properly. The turbo versions delivered up to 50 percent more power from the same cylinder count compared with the comparable Roots-blown engine.

For marine propulsion, EMD offered three configurations from the 645 line:

645E6 (Roots-blown). Available in 8, 12, and 16 cylinders, this is the mechanically simple variant aimed at smaller workboats and vessels with straightforward power requirements. Ratings run from 1,052 hp (8 cylinders) through 1,501 hp (12 cylinders) to approximately 1,950 hp (16 cylinders), all at 900 rpm. The maritime propulsion directory lists the 8-645E6 at 1,052.3 bhp and the 12-645E6 at 1,501.3 bhp.

645F7B (turbocharged). An 8-cylinder turbocharged variant rated from 1,700 hp upward; the 12, 16, and 20-cylinder turbocharged variants scale proportionally. Operators replacing aging Roots-blown 645s with turbocharged units in the same engine room sometimes picked up 30 to 40 percent more continuous power from the same footprint.

The 645 was the dominant EMD marine and stationary engine from the late 1960s through the 1980s. Its last newly manufactured locomotive engine was built in 2008 for an Indonesian customer, but the marine and stationary service population was larger than the locomotive fleet in terms of total installed hours, and parts continued to flow through EMD’s LaGrange service operation for years after.

A 6,140-hp towboat delivered to the Ohio River in 2011 still carried a pair of 12-710 engines as its upgrade path, but the trade-in involved 16-645E5 engines that the owner replaced specifically because the 710s burned an estimated 600 gallons less fuel per day per engine while delivering 400 more horsepower. That comparison underlines how much of the 645’s continuing commercial life was extension rather than new installation.

710 series: 1984 to present

The 710 replaced the 645 in production from 1984 onward. Per-cylinder displacement increased to 710 cubic inches (11,600 cm3) by lengthening the stroke to 11 inches (280 mm) while keeping the 645’s bore of 9 1/16 inches (230 mm). The 1-inch stroke extension accounts for the entire 65-cubic-inch displacement gain between the 645 and 710; the bore tooling is identical. The compression ratio is 15.3:1 in locomotive tune and 16:1 in marine and stationary applications. The 45-degree V-angle carries over; V8, V12, V16, and V20 configurations are all produced.

Maximum governed speed is 900 rpm for marine and stationary use, with an idle as low as 200 rpm available in the marine version. That 200-rpm idle is notable: it’s exclusive among medium-speed diesels of this power class and allows harbor tugs on fixed-pitch propellers to hold back thrust during slow maneuvers without blowing fuel through the system. The engine can accept full load in a single step from idle and recover rated speed in roughly two seconds in genset mode, or accelerate from idle to full propulsion load in under 11 seconds.

The 710 carries two features absent from all earlier EMD engines: it was offered only with turbocharging (no Roots-blown option at launch), and from 1995 onward, electronically controlled unit injectors replaced the mechanical units that had run in EMD engines since 1934. Electronic injection allowed variable injection timing matched to load, cutting fuel consumption and preparing the platform for future emissions compliance. Per Marine Reporter’s 1986 coverage of the 710G introduction, development and tooling for the new architecture cost a combined $138 million ($60 million development, $78 million tooling).

Dimensional progression across all three series

The crankshaft centers are compatible across 645 and 710, which eased the manufacturing transition in 1984 and continues to simplify repower jobs where an older 645 hull is refitted with 710 power. The engine mounts, flywheel housing dimensions, and many accessory drives carry over.

Two-stroke uniflow design: Roots blower, turbocharger, and the clutched hybrid

The defining technical character of every EMD marine engine since 1938 is uniflow scavenging: fresh air enters through ports in the lower cylinder wall uncovered by the piston as it passes bottom dead center, and exhaust exits through four poppet valves in the cylinder head. The charge flows in one direction, bottom to top, pushing combustion gases ahead of it and out through the valves before the piston closes the ports on its upward stroke.

Forcing air in at the bottom while extracting exhaust at the top requires either a mechanically driven blower or a turbocharger. The 567 and Roots-blown 645 variants use a Roots supercharger gear-driven directly from the crankshaft. The Roots blower runs continuously at a fixed ratio to engine speed, delivering a reliable positive pressure difference from the moment the engine turns. That simplicity is its main commercial virtue: no variable geometry, no lag at low rpm, and a parts population that any EMD-trained mechanic can rebuild in the field.

Turbocharged 645 and all 710 variants use a different arrangement. The primary unit is exhaust-driven, but at low speeds and low exhaust flow, an overrunning clutch on the turbocharger shaft disengages and a gear-driven blower takes over, ensuring adequate scavenging pressure through the full rpm range. When exhaust energy rises sufficiently at higher loads, the clutch releases and the turbocharger “comes off the gear,” operating as a pure exhaust-driven unit and achieving higher efficiency than any mechanically driven blower can match. This two-element system is sometimes called a compound or clutched-blower arrangement.

The clutched design solves a specific problem that pure turbocharged two-strokes encounter: the port-opening event in a two-stroke happens very briefly, and if differential pressure across the cylinder is too low, scavenging is incomplete and exhaust gas dilutes the incoming charge. At 200-rpm idle, exhaust energy is near zero; a pure turbocharger would stall. The gear-driven blower maintains the pressure difference. A ship’s engineer slowing a tug for a docking maneuver at 200 rpm still has reliable scavenging available; the engine doesn’t stumble when the propeller demands a burst.

The unit injector is the other distinctive feature. Each cylinder has a single injector unit that combines fuel metering and injection timing in one assembly bolted directly to the cylinder head, driven by a rocker arm from the camshaft. GM received a patent on the unit injector concept in 1934. From that date through the first electronic units in 1995, the mechanically timed unit injector changed remarkably little, which is one reason EMD parts are interchangeable across decades of production. An overhaul workshop that stocked 567 unit injectors in 1970 could still identify most of the tooling when rebuilding 710 injectors thirty years later.

The comparison with the Detroit Diesel 71 and 92 series, which also used two-stroke, loop-scavenged diesels with unit injectors, is instructive. Detroit Diesel used a loop-scavenged design without exhaust valves, relying entirely on port timing for both intake and exhaust. EMD’s uniflow design, with separate exhaust valves, achieves more complete scavenging at the cost of the valve-train complexity. Most large marine two-strokes, including the slow-speed crosshead engines from MAN and Wärtsilä, use uniflow scavenging for the same reason: it is more thermodynamically efficient at high specific power.

For a detailed treatment of how uniflow and loop scavenging compare in practice, see loop scavenging versus uniflow scavenging.

Marine and commercial applications

Inland waterways and Gulf Coast tugs

The US inland waterway system, running from the Gulf of Mexico up the Mississippi, Ohio, and Illinois rivers, is the sector where EMD marine engines have the strongest installed base outside the military. Moran Towing operated a harbor tug rated at 6,000 hp with a pair of EMD engines working Norfolk Harbor as of 2013. Marquette Transportation, which runs more than 100 towboats and tugboats on the Gulf Coast and inland river system, has been a long-term EMD customer. The Rick Calhoun, a 180-by-40-foot linehaul towboat delivered to Marquette by Gulf Island Fabrication in Houma, Louisiana, runs twin EMD 20-710G7C Tier 3 diesels producing 9,200 hp at 900 rpm combined, driving five-bladed stainless steel propellers in Kort nozzles through Lufkin RHS3200HG marine gears.

The engine’s attraction in this sector is straightforward. A towboat operating on the Ohio or Mississippi has limited access to specialist marine-engine service infrastructure away from the major ports. EMD’s dealer network, inherited from the locomotive business, reaches into the same inland cities that the rivers touch. Parts availability and technician familiarity are concrete operational assets, not marketing copy. An owner running EMD 710s on the Illinois River can draw on the same LaGrange parts depot that supplies a railroad 200 miles away.

The repower case is documented at the federal level. The Southeast Missouri Regional Planning Commission, in a MARAD-funded project, arranged for AEP River Operations to repower the towboat MV Daniel W. Wise with newer EMD 710 engines, replacing 1978-vintage Tier 0 EMD 645 engines. The calculated emissions benefit of that single vessel swap was 236 tons per year of NOx and 12 tons per year of particulate matter eliminated from the waterway air basin.

Offshore oil and gas

EMD 710 engines power both propulsion and generation on offshore support vessels and drilling rigs. For propulsion, the 8- and 12-cylinder variants fit supply boat engine rooms that need 2,000 to 3,000 hp per shaft from a medium-speed diesel without the footprint of a larger four-stroke. For power generation, skid-mounted EMD 710 gensets are certified to ABS and other class-society standards for installation on semi-submersible and jackup drilling platforms, where the units often run in parallel to support drilling drives, dynamic positioning thrusters, and hotel load simultaneously.

The specific advantage on a drilling rig is load response. A thrusters-off dynamic positioning fault can demand 2,000-plus kW of sudden load from a standing genset. The 710’s two-second full-load acceptance means the frequency deviation on the rig’s switchboard is brief enough that protective relays don’t trip drilling equipment.

Ollis-class Staten Island ferries and other passenger vessels

The highest-profile recent marine application for EMD engines is the three Ollis-class double-ended ferries built for New York City Department of Transportation service on New York Harbor. Each vessel is 320 feet long with a 70-foot beam and accommodates 4,500 passengers. Power comes from four EMD 12-710 engines per ferry, with two engines at each end driving an ABS Reintjes DUP 3000 P combining gear and a Voith Schneider propeller. The individual engines are rated at 2,495 hp at 750 rpm in the E 23B configuration. Total installed power per vessel: 9,980 hp. The first ferry, SSG Michael H. Ollis, entered service on New York Harbor in 2022.

These ferries were the commercial debut of the Tier 4 Final certified 710 E 23B. New York Harbor is within an Emission Control Area under MARPOL Annex VI, and the city specifically required Tier 4 compliance. Using SCR aftertreatment, the E 23B achieves NOx at 1.8 g/kWh and PM at 0.04 g/kWh, meeting both EPA Tier 4 Final limits and IMO Tier III standards. It was the first two-stroke engine for the marine market to receive that EPA certification, a milestone Progress Rail achieved in December 2016.

EPA Tier 4 and IMO Tier III compliance

Tier structure for Category 2 marine diesels

US EPA marine diesel emissions regulations divide commercial vessel engines into three categories by per-cylinder displacement. The 710 falls under Category 2, which covers engines with displacement from 7 to 30 liters per cylinder. Category 2 engines from 500 to 8,000 kW power the majority of tugboats, pushboats, supply vessels, and workboats operating in US waters.

Tier 1 and Tier 2 standards applied from the late 1990s through 2004 on a phased schedule. The 710G series in its then-current form met Tier 1 through combustion tuning and improved turbocharger efficiency. Tier 2 compliance came through further injection system development; the electronic unit injectors introduced from 1995 gave engineers control over injection timing and rate shaping that mechanical injectors couldn’t provide. EPA Tier 2 NOx limits for medium-speed marine diesels run from roughly 7.2 g/kWh at 900 rpm. IMO Tier II, applying to vessels built from January 1, 2011, onward, sets a limit of approximately 9.8 to 14.4 g/kWh depending on engine speed. The 710G7B in Tier 2/IMO II certified form met these targets through combustion optimization alone, without aftertreatment.

Tier 3 and Tier 4 Final

The 12-710 engine that became EMD’s 500th medium-speed marine engine delivery in July 2013 was certified simultaneously to US EPA Tier 3 marine and IMO Tier II. EPA Tier 3 sets NOx limits of approximately 3.4 to 1.96 g/kWh for the 900-rpm speed class. The 8-cylinder 710 announced in 2013 at 2,500 bhp carries the same Tier 3/IMO II certification.

Tier 4 Final for Category 2 marine engines requires NOx at 1.8 g/kWh and PM at 0.04 g/kWh. IMO Tier III, applying to ships in ECAs from January 1, 2016, demands an 80 percent NOx reduction against Tier I baseline. The 710 E 23B achieves both through a selective catalytic reduction system that fits within the same engine-room footprint as the pre-Tier 4 installation: the 12-cylinder variant maintains the same external dimensions as its predecessors, which matters commercially because vessel owners can’t always accommodate a larger engine.

Progress Rail certified the E 23B in December 2016 at the International Workboat Show in New Orleans. The Ollis-class Staten Island ferries, contracted in 2017 and delivered from 2022, were the first major commercial order for the Tier 4 engine. IMO Tier III applies only in Emission Control Areas. Outside an ECA, the 710 can operate in a Tier II mode without SCR reagent consumption, a two-mode capability that matters to operators trading between ECA and non-ECA waters. For the full regulatory framework governing two-stroke engines in ECAs, see Tier III compliant two-stroke engines.

Aftermarket overhaul and repower ecosystem

OEM support through Progress Rail

Progress Rail’s engine support operation extends through three channels. The Mayfield, Kentucky facility is the EMD engine remanufacturing Center of Excellence, where complete rebuilds of 567, 645, and 710 engines are carried out to OEM specifications and tolerances. Mayfield covers all emission tiers from the original unregulated Tier 0 through Tier 4 configurations. The LaGrange, Illinois service organization handles engineering support and parts distribution for North America. Authorized distributors in Europe and Asia-Pacific carry inventory for the marine and stationary segment separately from the locomotive business.

Progress Rail offers a factory exchange program for unit injectors and turbocharger cores. Both are high-wear items with overhaul intervals measured in thousands of hours; the exchange program lets a vessel operator swap worn cores for factory-rebuilt units at the pier without waiting for a rebuild cycle. OEM remanufactured injectors are rebuilt to the internal specifications of the original engineering drawings, which matters for the fuel-injection precision that Tier 3 and Tier 4 certifications depend on. A non-OEM injector that doesn’t hold the certified injection timing window can push the engine out of its certified NOx envelope.

Third-party overhaul market

The 567, 645, and 710 families support a substantial independent overhaul sector alongside the Progress Rail OEM channel. The engines’ dimensional consistency across generations means a third-party machine shop that remanufactured 645 cylinder liners in the 1980s can retool for 710 work because the bore is identical. Power assemblies, which consist of the cylinder liner, piston, rings, and connecting rod as a matched set, are commercially available from multiple independent suppliers in the US, as is the tooling for cylinder liner replacement.

The 710’s cylinder liner replacement procedure is designed to be completed by a vessel’s crew using standard marine engine tooling, without requiring the engine to be lifted from its mounts. That design choice, made in the 1980s, keeps a critical maintenance operation accessible to inland waterway and coastal operators whose vessels never berth near a machine shop.

Repower programs and fleet life extension

The 645-to-710 repower path is the most common EMD fleet-upgrade pattern in the marine segment. Because the engine mounts and crankshaft centers are compatible, a vessel built around a V16 or V20 645 can receive 710 power without structural modification to the engine room. The documented outcome on the MV Daniel W. Wise and similar towboats is a fuel consumption improvement consistent with the 710’s higher compression ratio and electronic injection, combined with meeting current emission standards from a platform built before Tier regulations existed.

Progress Rail also offers the EMD 710ECO locomotive repower package, which upgrades older locomotives to Tier 3 or Tier 4 compliance using 710 power assemblies and electronic controls. The marine equivalent is a less formalized program, but the component-level compatibility is the same: a marine operator can specify Tier 3 or Tier 4 certified power assemblies when overhauling an existing 710 installation, provided the SCR system and exhaust modifications are also installed.

Ownership timeline: GM to Greenbriar to Progress Rail

The General Motors era (1941 to 2005)

From 1941 through 2004, EMD operated as a division, then a wholly owned subsidiary, of General Motors. The locomotive business was the primary revenue driver; marine and stationary sales were a secondary but steady segment, especially during the wartime and postwar decades when EMD engines went into US Navy support vessels, Coast Guard cutters, and civilian workboats in large numbers.

Cleveland Diesel Engine Division carried the marine and stationary product lines from 1941 to 1962. When GM dissolved Cleveland Diesel in 1962 and folded its operations into EMD, the LaGrange facility became responsible for the full three-market product range. The 645 series launched in 1965 was the first EMD engine family designed from the outset to serve locomotive, marine, and stationary markets from a single platform.

By the early 2000s, GM was under financial pressure from its automotive business. The company announced the sale of EMD in January 2005.

Greenbriar and Berkshire Partners (2005 to 2010)

The sale closed April 4, 2005. Greenbriar Equity Group and Berkshire Partners, a private equity partnership, acquired EMD from GM for an undisclosed sum. At that point, the company was renamed Electro-Motive Diesel, Inc., taking the “EMD” brand from an abbreviation of a division name to a standalone corporate identity.

The private equity period lasted five years. EMD continued locomotive production at LaGrange and maintained its marine and stationary engine lines. The 710 series was the primary product; the 645 was available on a by-request basis for operators who needed spare parts commonality with existing installations.

Progress Rail and Caterpillar (2010 to present)

On June 1, 2010, Caterpillar announced that its subsidiary Progress Rail Services would acquire EMD from the Greenbriar/Berkshire partnership for $820 million in cash plus an estimated$108 million net working capital adjustment. The transaction closed August 2, 2010. EMD became a brand of Progress Rail, which is itself a wholly owned subsidiary of Caterpillar Inc.

The acquisition made Caterpillar the owner of two medium-speed marine engine brands with different technical lineages: the Cat M-series (four-stroke, from the MaK acquisition in 1997) and the EMD 710 (two-stroke, from 2010). Both sell under the broader Caterpillar umbrella but occupy different market segments and are sold through separate channels. Cat Marine handles the Cat-branded products; Progress Rail handles EMD. The Caterpillar marine corporate history article covers the M-series side of that combined picture.

EMD celebrated its 100th anniversary in 2022. Illinois Railway Museum hosted the celebration event on August 20, 2022. Progress Rail marked the occasion by noting that the LaGrange design center, which had been EMD’s home since 1935, remained the engineering and manufacturing base for both rail and marine EMD engines.

Corporate ownership timeline

710G marine power ratings

The 12-cylinder variant is the most common marine configuration. EMD delivered its 500th medium-speed marine engine, a 12-710 rated at 3,000 bhp, in July 2013. That engine was certified to US EPA Tier 3 marine and IMO Tier II simultaneously, destined for a US-flagged tugboat with a fixed-pitch propulsion system. At that point the three-series legacy, 567 plus 645 plus 710, had crossed 72,500 engines delivered worldwide.

For genset applications, the 710 covers a continuous output range from 745 to 3,580 kW at 60 Hz/900 rpm and 570 to 2,980 kW at 50 Hz/750 rpm. Offshore drilling operators, including semi-submersible and jackup rig owners, selected EMD 710 gensets for the engine’s load-acceptance speed: dynamic positioning systems demand rapid power response when thrusters cut in or out, and the 710’s two-second recovery from full-load step change is competitive with any four-stroke alternative in the class.

Position in the US medium-speed marine market

EMD occupies a specific corner of the global marine engine market. It is a North American brand with particular strength in the US inland waterway system, the Gulf of Mexico workboat fleet, and US Navy and government contracts. Outside North America, its installation base is thinner; the European medium-speed market is dominated by MAN, Wärtsilä, and the Cat M-series, and Asian markets favor domestic builders such as Yanmar and Hanshin for smaller vessels. EMD held roughly 30 percent of the North American diesel-electric locomotive market as of 2010; the marine percentage is harder to pin down from public sources but follows a similar pattern of North American concentration.

The acquisition by Progress Rail and Caterpillar in 2010 formalized something that had been commercially true for decades: EMD marine engines now share a dealer and parts infrastructure with Cat marine products in the Americas, meaning a dealer who stocks Cat 3500 parts for a tug fleet also has access to the EMD supply chain for a neighboring operator with 710s. That overlap doesn’t eliminate brand separation, but it reduces the friction of running mixed fleets.

The 1010J four-stroke engine, introduced by Progress Rail in 2015, is a Tier 4-rated 4,600-hp unit for the locomotive market that derives from the earlier 265H design. It doesn’t have a current marine variant, so the 710 remains the active two-stroke marine product line.

Limitations

The scope of this article covers the EMD 567, 645, and 710 engine families in marine and naval applications. The following limits apply.

Commercial sales volumes, customer-specific contract prices, and the split between locomotive and marine revenue are not disclosed by Progress Rail or Caterpillar. The production figure of 72,500 engines across all three series, cited by EMD in 2013, is the most recent authoritative aggregate; it covers all applications including locomotive.

The 710 series remains in production as of 2026, but specific annual output figures for the marine and stationary segment are not in the public domain. The 1010J engine is included only briefly because it has not, as of available sources, been offered in a marine variant.

Military contract details beyond the publicly documented WWII LST program are not covered here. US Navy surface combatant main propulsion and generator configurations for current and recent vessels may include EMD equipment under contracts that are not publicly disclosed in detail.

The emissions compliance section covers EPA Category 2 medium-speed marine standards. The Category 3 standards (applicable to large propulsion engines above about 130 liters per cylinder) apply to larger slow-speed and some medium-speed engines, not to the 710. IMO Tier III applies to vessels built from January 1, 2016, and applies only within ECAs; the legal and technical interaction between Tier III and trading-pattern decisions is covered in the Tier III compliant two-stroke engines article.

Service manual details and warranty terms are subject to change by Progress Rail. For current ratings, certifications, and service support, the Progress Rail marine and stationary engines page at progressrail.com is the primary source.

See also

• Marine engine makers
• Caterpillar marine corporate history
• Detroit Diesel marine 71 and 92 series
• Uniflow scavenging in two-stroke marine engines
• Loop scavenging versus uniflow scavenging
• Cooper-Bessemer marine engines
• Tier III compliant two-stroke engines