The EMD 567 Engine That Silenced Steam in 1938
In 1938, a single locomotive changed everything.
The EMDFT rolled out of Laange, Illinois, powered by a pair of 567 engines that would kill steam locomotives across America.
But the real insanity wasn’t just that it worked.
It was how a two-stroke engine design that most engineers said couldn’t scale became the most successful locomotive power plant in history.
This is the story of the EMD567, the engine that redefined what railroad power could be.
When electromotive introduced the 567 in 1938, conventional wisdom said two-stroke engines were too crude for railroad service.
Four-stroke engines were smoother, more refined, and theoretically more efficient.
But EMD’s engineers understood something their competitors missed.
Railroads didn’t need refinement.
They needed power, reliability, and above all, availability.
The 567’s two-stroke uniflow design featured intake air entering through ports in the cylinder liner, while four puppet type exhaust valves in the cylinder head expelled burnt gases.
Every revolution of the crankshaft produced a power stroke, doubling the firing frequency of four- stroke competitors.
This wasn’t just about power density.
It was about mechanical advantage.
With an 8.5 in bore and 10-in stroke, each cylinder displaced 567 in, more than most entire automobile engines.
A 12cylinder 567 totaled 6,84 in.
And the 16cylinder version reached 9,72 in of displacement, making it one of the largest and most powerful locomotive engines of its era.
But displacement alone didn’t explain the 567 success.
The real genius was in the details that made it work under railroad conditions.
The 45° V configuration kept the engine compact with good balance and a short overall length.
Unit injectors were mounted at each cylinder and actuated by the engine cam shaft, eliminating external high-pressure lines and separate injection pumps used by some competitors.
The geardriven accessories meant no belts to slip or break.
The crankase was a masterpiece of foundry work.
Cast in mianite iron, it provided the rigid foundation needed to handle the massive forces generated by 16 cylinders firing in rapid succession.
The crankshaft itself was a forged steel monster with throws precisely balanced to eliminate vibration even at maximum power.
Each connecting rod was machined from a single steel forging with bronze bushings that could be replaced during routine maintenance.
Most importantly, the 567 was designed for railroad duty cycles, not the transient loads that truck engines faced.
Railroad engines ran at constant RPM for hours, sometimes days.
They needed to produce maximum torque at 800 RPM and hold it indefinitely.
The 567’s long stroke and conservative tuning delivered exactly that kind of sustained power.
The Roots blower was critical to making the two-stroke cycle work.
Unlike a turbocharger that depended on exhaust energy, the mechanically driven blower provided consistent air flow regardless of load.
At idle, it scavenged exhaust gases and filled cylinders with fresh air.
Under load, it provided the positive pressure needed to pack maximum air into each cylinder during the brief scavenging period.
This scavenging process happened in milliseconds.
As the piston descended, it uncovered intake ports in the liner.
Pressurized air from the roots blower rushed in, forcing exhaust gases out through the open valves in the head.
The Uniflow design meant air and exhaust never mixed, ensuring complete combustion and maximum power from every drop of fuel.
The fuel injection system was equally sophisticated despite its apparent simplicity.
Each cylinder had its own unit injector, a self-contained system that combined high-pressure fuel pump and injection nozzle in a single unit.
The unit injectors were actuated by the cam shaft running at crankshaft speed, providing precise timing without external high-press fuel lines.
Steam locomotives were mechanical marvels, but they were also maintenance nightmares.
A typical steam engine required daily servicing, weekly boiler washes, and monthly major inspections.
When something broke, repairs meant weeks in the shop and armies of specialized craftsmen.
The 567 changed all of that with one revolutionary concept, the power assembly.
Each cylinder was a complete self-contained unit.
The power assembly included the cylinder liner, piston, connecting rod, piston carrier, and cylinder head, all bolted together as a single module.
When a cylinder needed service, mechanics didn’t tear down the entire engine.
They simply unbolted the power assembly and lifted it out with an overhead crane.
The process took hours, not weeks.
A railroad could pull a power assembly in the morning, install a rebuilt unit by afternoon, and have the locomotive back in service by evening.
The removed assembly went to the shop for rebuilding while the locomotive kept earning revenue.
This wasn’t just convenient, it was revolutionary economics.
The power assembly concept included a wet cylinder liner design that could be removed as a complete unit without disturbing the engine block.
The piston was a two-piece aluminum design with steel crown and aluminum skirt, optimized for the thermal stresses of two-stroke operation.
The connecting rod featured a marine style bearing that could be inspected and replaced without removing the piston.
Common parts across the entire 567 family multiplied these advantages.
Whether a railroad operated V6, 8, 12, or 16 engines, the power assemblies were identical.
A single parts inventory served the entire fleet.
Mechanics trained on one engine could service them all.
The economies of scale were enormous.
The standardization went deeper than just power assemblies.
Fuel injectors, governors, water pumps, and oil pumps were common across the entire family.
Even the electrical components followed standard patterns with identical generator configurations and control systems regardless of engine size.
This parts commonality was unprecedented in the locomotive industry, but EMD’s real master stroke was selling complete systems, not just engines.
The 567 came integrated with EMD generators, traction motors, control systems, and most importantly, comprehensive support.
EMD provided detailed maintenance manuals, training programs, and field service representatives who understood that railroad time was money.
The training programs were particularly innovative.
EMD established schools where railroad mechanics could learn 567 maintenance procedures using actual engines and components.
The company provided detailed cutaway models that showed internal operation along with specialized tools designed specifically for 567 service.
This investment in education paid dividends and reduced downtime and improved reliability.
The integration advantages were impossible for mix and match competitors to overcome.
The modular design also meant that improvements could be incorporated without scrapping existing engines.
As EMD developed better pistons, improved injectors, or enhanced cylinder heads, these upgrades could be installed during routine power assembly changes.
A 567 could evolve over its service life, staying current with the latest technology.
Let’s separate fiction from fact and what’s actually true about the 567 from the sound it makes to why many surviving 567s carry 645 guts.
People credit the turbo, but the 567 sound comes from the two-stroke firing every revolution, the roots blower moving air each cycle, and the exhaust valve timing that sets the rhythm.
That mix creates the chuff and wine everyone recognizes.
The exhaust valve timing was particularly critical.
Each cylinder had four exhaust valves operated by a single camshaft lobe through a rocker arm system.
The valves opened just after the power stroke peak and closed as the piston uncovered the intake ports.
This timing had to be precise within a few degrees or the scavenging process would fail and the engine would lose power dramatically.
But here’s where it gets confusing.
Many locomotives identified as 567s today actually carry 645 power assemblies inside 567 crank cases.
The external dimensions of 645 power assemblies were designed to fit 567 C and 567D engine blocks, allowing railroads to upgrade their engines without replacing the entire power plant.
These hybrid engines blur the line between families, creating locomotives that look like 567s, but perform like 645s.
The upgrade path was economically brilliant.
Instead of scrapping perfectly good locomotives when parts became scarce, railroads could install 645 power assemblies and extend service life by decades.
The 567 crankcase remained along with the basic engine architecture, but the cylinders, pistons, and heads were pure 645 technology.
These engines often carried more power than original 567s, but they weren’t true 645s either.
Peak horsepower was never the 567’s primary selling point.
It was availability measured in hours to repair, not weeks.
A typical 16cylinder 567 C engine produced around 1,600 horsepower, which was respectable, but not revolutionary.
It used Woodward PG electro-hydraulic governors to precisely control engine speed by varying fuel delivery to the unit injectors, providing stable operation under varying loads.
The governor could be adjusted for different applications from the constant speed requirements of passenger service to the variable load demands of freight operation.
The 567D’s turbocharger system used a gearass assisted drive at low engine speeds and transition to exhaust driven operation as load increased with its center section lubricated by oil to handle the demanding conditions of railroad service.
At that point, the overrunning clutch disengaged and the turbo freew wheeled on exhaust energy alone.
This system eliminated turbo lag and provided consistent power across the entire operating range, but it was mechanically complex and required precise timing to work properly.
The turbocharger itself was a specialized unit designed specifically for the 567D.
Unlike automotive or marine turbos, it was built to handle the unique exhaust characteristics of a two-stroke engine with rapid pressure pulses and high temperatures.
The 567D’s turbo is gear assisted at low speed via an overrunning clutch, then rides exhaust energy as load rises.
The center section is oil lubricated and charge air is cooled by a waterto-air aftercooler.
The FT locomotive that debuted in 1939 was EMD’s proof of concept, but it was the postwar models that truly established the 567’s dominance.
The GP7, introduced in 1949, put 567 power into a versatile road switcher configuration that could handle everything from freight drags to passenger locals.
The GP9 that followed in 1954 refined the concept with improved electrical systems and higher horsepower ratings.
The GP7’s 1,500 horsepower came from a 567B engine that could run continuously at maximum output.
The GP9 pushed that to750 horsepower with a 567C.
But the real advantage was operational flexibility.
A single GP9 could replace multiple steam engines in yard service, then head out on the road for a freight run.
The electrical system integration was crucial to this versatility.
The 567 drove a DC generator that fed current to traction motors mounted on the trucks.
This electric transmission provided infinite speed control and allowed the engine to operate at its most efficient RPM regardless of train speed.
The system could also provide dynamic braking, using the traction motors as generators to slow heavy trains on mountain grades.
The switcher variants told a different story.
SW7 9 and 1200 locomotives use smaller 567 engines and configurations optimized for yard work.
These engines spent their lives at idle or low power, starting and stopping constantly as they assembled trains.
The 567’s two-stroke design handled this duty cycle better than four- stroke competitors, which suffered from carbon buildup and poor combustion at low loads.
The SW1200 was particularly significant because it demonstrated the 567 scalability.
Using a V12 configuration, it produced 1,200 horsepower in a compact package that could navigate tight yard track.
The engine was essentially 2/3 of a GP9 power plant, sharing the same power assemblies and maintenance procedures, but optimized for switching service.
Passenger service demanded different priorities, and EMD delivered with e-units powered by twin 12567 engines.
The E7, 8, and 9 models could maintain 100 mph schedules while providing the reliability that passenger service demanded.
Unlike steam engines that required water stops and coal changes, e-units could run coast to coast with only fuel and routine inspections, the twin engine configuration wasn’t just about power.
It provided redundancy that steam couldn’t match.
If 1567 failed, the eun could continue on the remaining engine, albeit at reduced speed.
This reliability was crucial for passenger trains operating on tight schedules with no backup equipment available.
The e-unit design also showcased the 567’s adaptability.
The engines were mounted longitudinally in the carbid driving separate generators that fed a common electrical system.
This arrangement allowed for different power combinations and provided the smooth acceleration that passenger service required.
The streamlined car bodies became icons of American passenger railroading.
But the 567’s influence extended far beyond EMD’s own locomotives.
Competitors studied the design and tried to copy its advantages, but they missed the integration that made it work.
The 567 wasn’t just an engine.
It was the centerpiece of a complete system that included electrical components, control systems, and service support designed to work together.
As steam disappeared from American railroads in the 1950s, the 567 became the sound of progress.
Round houses that once echoed with the hiss of steam and clang of hammers now hummed with the steady rhythm of 567s at idle.
The skills needed to maintain these engines were different from steam, but they were also more standardized and easier to teach.
The transition wasn’t always smooth.
Railroad workers who had spent careers maintaining steam engines had to learn entirely new skills.
But the 567’s comprehensive documentation made this transition easier than it might have been.
EMD’s training programs helped bridge the gap between steam and diesel expertise.
The afterlife of 567 engines proved their durability.
As major railroads retired first generation diesels in favor of newer technology, 567 powered locomotives found new homes on shorelines in museums and in industrial service.
Marine conversions put 567s to work, powering tugboats and fishing vessels, where their reliability and simple maintenance requirements were valued over fuel efficiency.
Stationary power applications embraced 567 engines for emergency generators and standby systems.
Hospitals and critical facilities installed 567 power generators that could start instantly and run indefinitely during power outages.
The same characteristics that made them ideal for railroad service, constant speed operation, and bulletproof reliability translated perfectly to these applications.
Industrial operations discovered that 567 engines were ideal for powering equipment that required constant reliable power.
Sawmills, mining operations, and manufacturing plants installed 567 power generators and compressors that could run continuously with minimal maintenance.
The engines that had revolutionized railroading found new purpose in keeping American industry running.
Today, 567 engines continue operating in applications where newer technology can’t match their combination of simplicity and durability.
Tourist railroads rely on 567 powered locomotives to haul passengers on scenic excursions, while industrial operations use them for switching and plant railroad service.
The engines that killed steam have themselves become historical artifacts, but they’re artifacts that still work.
