Materials:
All structural members and brackets are constructed of carbon steel. The 14" guide
wheels for DMF RW-1420 railgear are machined from hardened steel
castings and are fitted to high strength alloy steel axles with
heavy-duty tapered roller bearings.
Installation:
Both DMF front and rear guidewheel units bolt to the truck frame using
only hand tools found in any shop. They are designed to minimize the
amount of space required and in many cases fit within the
existing
boundaries of the vehicle. The front units, however, sometimes require a
bolt-on frame extension to complete the installation. Rear RW-1420 railgear mounts below the top of frame and directly behind the chassis
spring hangers.
Brakes:
The optional RW-1420 rail brakes are an external Cobra shoe style and
can be either air or hydraulically actuated. In both cases the rail
brakes are applied simultaneously with the truck brakes when the
operator presses the brake pedal. Both systems also have a
dashboard-mounted switch that permits the operator to enable or disable
the rail braking system.
Air rail brakes use a truck style air
chamber to supply the clamping force. Supply pressure can come from the
vehicle's air system (preferred) or from optional skid mounted compressor. A pressure protection valve separates the railgear and the
truck's air system, preventing a failure in the rail brake system
from adversely affecting truck braking.
The hydraulic rail brake option requires
the installation of a hydraulic power unit to provide the braking force.
When the dashboard mounted enable switch is turned on, the brake lamp
signal is used as a trigger to run the pump and divert hydraulic
pressure to the brakes. A built in safety circuit protects the truck’s
brake lamp system as well as the hydraulic power unit from excessive run
times.
Operation:
The truck is pulled onto a crossing and
the wheels aligned to the tracks with attention being paid to the front.
The operator then activates the hydraulic power unit by pulling the lever of the hydraulic valve
to raise the railgear off of the pin-off device. The safety pins are
removed and the lever pushed forward lowering the rail wheels to the
track. The front gear will lift the front of the truck and go over
center. The rear is operated similarly. The gear is raised to lift the
weight from the pin-offs, and the pins are removed. The gear is then
lowered via the two handled valve at the rear of the truck. Each spool
may be operated independently to articulate the rear gear and engage the
rail even if the rear wheels are not perfectly aligned. Once the rear
gear is fully deployed, the pin offs are re-inserted to lock the gear in
place.
Steering Wheel Lock:
The steering stop is provided with the
optional railwheel brake assembly, as in the RW-1630 gear. If the unit
is not equipped with optional brakes, a steering wheel lock is provided,
requiring no modifications to the column.
DMF's RW-1420 railgear is a scaled down
version of our patented and very successful RW-1630 gear for large
trucks. The front guidewheel assembly attaches to the frame and front
axle and lifts the front wheels off the track, thus utilizing the
vehicle's front suspension. This design supports the vehicle as it was
intended and helps the truck navigate curves smoothly and damp out the
effects of track irregularities. The rear assembly attaches directly to
the truck frame behind the rear axle spring hanger. It deploys with an
articulated dual scissor action that allows the rear railgear to be
moved both vertically and horizontally. This mechanism provides
the "side shift" action which has made DMF gear so well known in the
industry. It gives operators a greater margin for aligning the vehicle
to the track which speeds and simplifies the process of getting the
vehicle on rail.
