Evans Auto Railer
In the late 1930's, Evans Products of Detroit, Michigan marketed the Evans Auto Railer. This was the first commercially available road to rail conversion system. The term "Hy-rail" is commonly applied to all conversion systems like this, but "Hy-rail" is a registered trademark of Fairmont Railways Motors.
The Auto Railer was available in several different versions. The bus style vehicle shown above and below was available for inspection, passenger, freight or mixed service. It could be built to accommodate from 12 to 27 passengers. The ability to run on the pneumatic road wheels was said to give it a very smooth ride. A major feature was the ability to go from the rail to the road without stopping. The vehicle could be ordered with the rear section removed and a two way dump body added or with a simple flat platform for use as a M.O.W. pick up or tower service car on electric railroads.
The company provided a standard coupler in the rear so the unit could function as a light locomotive, hauling one or two standard freight cars. The phantom view below shows the coupler.
I've found no pictures of their Tractor-trailer unit, but they advertised a unit that was equipped with a fifth wheel. This unit was designed to tow a standard semi-trailer. The unit was designed to haul the semi from one loading dock to the tracks. After negotiating the railroad tracks to its destination, it would leave the tracks and drop it off at the customer's loading dock. Needless to say, this idea never caught on.
The more familiar form of road to rail conversions was for trucks. Both two and three axle trucks could be converted.
The Evans system used air pressure to raise and lower the guide wheels. Only a small part of the vehicle weight rested on these wheels.
When used on three axle trucks, the rear unit was mounted between the axles.
This front view shows the air cylinder and spring in the center. The upper end was attached to a special sub-frame. The lower end was fitted to a universal joint and attached to a leaf spring. Two arms provided side to side alignment.
A heavier version (above right) used two extra spring-loaded supports.
The Burlington's 1941 Ford Woody had modified front body work to hide the retracted rail wheels. The chassis was raised and extensively strengthened. The 1941 Ford sedan (below) was also used by the Burlington.