Rail Car Systems The standard NAVCO ® Railside Car Shaker is comprised of a unidirectional piston type drive assembly, a pneumatic positioning cylinder and a heavy duty steel chassis. Operation of the NAVCO ® Railside Car Shaker is easily managed by one person. The controls can be stationed nearby or at a remote location. When the Railside Car Shaker is started the positioning cylinder is activated to extend the chassis so that the contact beam rests firmly against the rail car. Next the drive assembly is energized and loading or unloading begins. Once loading or unloading is completed the drive is de-energized and the positioning cylinder deactivated, causing the chassis to return to its retracted position. The standard NAVCO ® Railside Car Shaker is available in both pneumatic and electric models. The Roller Railside is manufactured with heavy duty steel rollers at the contact point for continuous unloading of captive cars. Portable Railcar Vibrators HCP hopper car vibrators are ideal for unloading dry bulk material from bottom dump railcars. The universal mounting head of the HCP fits all dovetail brackets found on hopper cars.