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DERAILERS – FITTING – ALDON
DERAILERS – FITTING

DERAILERS FITTING (MADE IN USA)

HOW TO GET A GOOD DERAIL FIT

Measuring Height of Rail
To be effective, a derail must be correctly sized for the
rail it is installed on, and adjusted in height so that the
derail block (the part that swings onto the rail) lies flat
on the surface of the rail. There are many sizes of rail to be
found in industrial spur tracks. The first step to insuring a good
derail fit is to carefully measure the height of the rail above the
sleepers. The simplest way to make this measurement is to
place a 1524mm steel bar or pipe across the rails and measure
up from the tie with a ruler, keeping close to the rail against
which the derail will be installed. Read to the nearest 3.2mm
(1/8”). LOCOMOTIVES & RAIL CAR STOPPING DEVICES
Crop the Tie Plates

The derail sits on two ties and Mark each sleeper plate about 25mm away from the rail base. Use a
must be pushed up against the metal-cutting power saw or a torch. If using a saw, remove the spike
rail head. The tie plates inside on the gauge side and cut the plates. If using a torch, you will need to
the rail will get in the way, so it is remove the two sleeper plates from under the rail, crop them, and then
necessary to crop the plates close to reinstall them under the rail, re-spiking the outer portions of the plates.
the base of the rail. The derail base Do not, as a short cut, permanently remove the sleeper plates.
must sit flat on the sleepers. They are needed to support the rail and hold to gauge.

Adjusting Derail to Rail Height
The underside of the derail block must be level
with the top of the rail.
It may be necessary to either notch the two sleepers to
lower the derail, or use metal shims to lift the derail. To
lower the derail, make a series of kerf cuts in the two ties.
Maximum notching depth: 9.5mm. To raise the derail,
use 6.4mm (1/4”) and 3.2mm (1/8”) Aldon steel shims.
Maximum shimming height: 12.7mm (1/2”). www.specialisedforce.com.au

Too High Too Low Just Right
There should be no space between A derail block that does not lie flat Derail block lies flat on rail; derail
derail block and top of rail will cause a failure to derail base sits flat on ties

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