DMF raildogs are a safety device that attach to the truck frame of a hi-rail vehicle and clamp to the head of the track. They are used on trucks that can experience shifting loads such as a DMF Roto-180 that is dumping ballast or a boom truck doing heavy trackside picks. In the event of a sudden load shift, the raildogs may prevent or at least minimize the effects of a tipping accident.
DMF raildogs come in both manual and hydraulic versions. The manual style has a slide collar that is lowered into place and secured by means of a manually-threaded lock screw. They are less expensive, more lightweight, and take up less space along the truck frame than their hydraulic counterparts. However, the hydraulic raildogs are much quicker and easier to lock and unlock. They will save a great amount time if the truck must make many small moves between clamping and unclamping evolutions.
DMF raildogs are NOT designed to be a stabilization device for regular use and because track is not designed to withstand strong upward forces the raildogs should never pull against the track during normal operation. Raildogs are considered a backup safety device used to minimize the effects of a tipping accident. They are not a substitute for outriggers and careful operation of on-track equipment. Strong forces transferred to the track by means of raildogs can damage, misalign and even lift rail in extreme instances.