In 1970, Soviet engineers took a standard ER22 railway carriage, bolted two jet engines from a Yakovlev Yak-40 airliner to the roof, and sent it screaming down the tracks at 250 kilometres per hour. This was not a fever dream. This was Soviet transport policy. The SVL — Skorostnoy Vagon-Laboratoriya, or High-Speed Laboratory Car — was the Soviet Union’s attempt to answer a question that Western nations were also asking: could jet propulsion make trains fast enough to compete with aircraft on short-haul routes?

Aviation Engines on Rails

The concept was straightforward, even if the execution was audacious. The SVL used its wheels only for guidance and support — not for propulsion. All forward thrust came from the two Ivchenko AI-25 turbofan engines mounted on the roof, the same engines that powered the Yak-40 regional airliner. The railway carriage simply rode the rails while the jet engines pushed it forward, like strapping a rocket to a shopping trolley. The AI-25 engines were relatively small and efficient by jet standards — each produced about 1,500 kilograms of thrust — but on a vehicle with steel wheels on smooth rails, that was more than enough. Friction was minimal. Aerodynamic drag was the primary limiting factor, and at 250 km/h, it became significant.

What They Learned

The SVL was never intended to become a production vehicle. It was a research platform — a moving laboratory designed to gather data on high-speed rail dynamics that the Soviet Union could not obtain any other way. At 250 km/h, phenomena like rail oscillation, wheel-rail contact dynamics, aerodynamic buffeting, and braking behaviour were fundamentally different from anything encountered at conventional speeds. Soviet engineers instrumented the carriage with sensors measuring every conceivable parameter: lateral acceleration, vertical bounce, yaw rate, air pressure distribution, noise levels, and structural stress. The data fed into the development of future high-speed rail concepts and helped Soviet railway engineers understand the limits of their existing track infrastructure.

The Jet Train That Time Forgot

The SVL was not alone in the jet-train concept. The United States experimented with the M-497 Black Beetle in 1966 — a modified Budd Rail Diesel Car with two General Electric J47 jet engines from a B-36 bomber strapped to the roof. It reached 295 km/h on a test track in Ohio. France, Germany, and Japan were all pursuing high-speed rail through more conventional means, and their approaches — electric traction, purpose-built track, aerodynamic trainsets — ultimately won. The SVL sits today as a rusting relic, a monument to an era when Soviet engineers believed that any problem could be solved by bolting a jet engine to it. They were not always wrong. But the future of high-speed rail belonged to the TGV, the Shinkansen, and the ICE — not to jet engines on the roof of a railway carriage.

Sources: Archived Dreams (Instagram), Soviet railway engineering archives