UNAC 20TRR military

The 20TRR is a high-capacity road-rail excavator that can perform earthwork tasks directly from a railroad track with great freedom of movement and with a large lifting capacity.


The 20TRR is a self-propelled vehicle with hydrostatic drive. This road-rail excavator is intended for any railway works. This vehicles is initially a Caterpillar excavator on which is maintened the same boom kinematics as the original machine and then modified in order to benefit from:
  • Setting up of clipped counterweight to lift huge loads
  • A sophisticated UNAC SMART-CS peripheral-view and operator indication system to receive real-time information regarding the machine, its load, and tilt, and to configure limits.
  • Two UNAC-HDTP motorized rail axles for hydrostatic driving and braking, without necessity of oscillating axle - Exclusive UNAC concept.


  • Very safe system, satisfying the most stringent road-rail standards, allowing to work under live wires
  • Real-time indication of track cant and load, without restraint on the machine
  • Very flexible axles that help to reduce risks of toppling and can tolerate high twists of tracks
  • Can work in both directions of the rail tracks thanks to the turret's continual full rotation and the rear-view cameras
  • Electronic security system for the boom's kinematics (different contact wire height levels) and for the rotation depending on a track's status (cant and slope, adjacent track side, etc...)
  • Great acceleration and deceleration when on tracks to optimize time spent on work sites, even under rain situation thanks to the full hydrostatic system on the railway wheels (no contact with tires)
  • Wide range of usable tools: auger, hydraulic rock breaker, buckets, hammers, universal pliers, hydraulic shears, mechanical pliers, compactor, clips with claws, loading bin, earthwork bin, and stripping beam
  • The Caterpillar initial warranty is officially maintained. The excavator benefits from the UNAC after-sales service and from Caterpillar’s dynamic after-sales network.
  • Maintains the original excavator's lifting and earthmoving workings capacities. The R/R excavator can lift 2T to a distance of up to 6m from the track centre, in an unfavourable cant situation and can therefore handle heavy equipment or also off-track works.
  • Possibility to make earthmoving and lifting from a track to the opposite side of the adjacent track
  • Equipped with a sophisticated system UNAC SMART-CS, which allows to work in safe and controlled space, and maximize the work space
  • Luxury/Comfort version cab of Caterpillar, getting an optimal ergonomic of the commands, and matching comfort, soundproofing, visibility and air conditionning.


Technical Data

  • Diesel CATERPILLAR C4.4, ACERT technology
  • Gross horsepower 147 hp / 108 kW at 2 000 rpm.
Road Transmission
  • Electronically-managed hydraulic traction system: 2 speeds
  • 4 driving wheels and 2 steering wheels
  • Speed: from 0 to 25 km/h
  • Speed regulator
  • Axle with a 30T capacity, oscillating front axle: +/-9°, lockable.
Rail Transmission
  • Hydrostatic, 4 wheel drive
  • Central hydraulic motor on each axle: POCLAIN
  • Speed: from 0 to 23 km/h.
Hydraulic Circuit
  • Two serial pumps and two pumps on PTO
  • Specific lifting mode: +7% of lifting capacity
  • Hydraulic tank: 135 L, 220 L circuit.
  • Hydraulic steering for 2 steering wheels
  • Mini turning radius: 8.90 m.
  • Road: the drive axles are equipped with multi-disk brakes with positive action for each wheel. The brakes are activated when the contact is broken, when the brake pedal is pressed, when the handbrake is pulled, when the left armrest is up, or when the emergency stop has been activated.
  • Rail: The hydraulic motors for the rail axles are equipped with positive action disks. The brakes are activated when the contact is broken, when the brake pedal is pressed, when the handbrake is pulled, when the left armrest is up, or when the emergency stop has been activated. A configurable PLC manages the acceleration and deceleration gradient of the rail axle motors.

Luxury/Comfort version, soundproof, ventilated, heated, air conditioned, seat with air suspension that can be adjusted specifically according to the driver’s weight. Steering wheel with adjustable inclination. An electronic dashboard and three digital displays from which the attachments can be controlled, the excavator’s status can be seen in real time, the blind spots (cameras) can be seen, and management of the dangerous movements.

Fuel Tank Capacity
  • Fuel tank: 235 L
  • Average autonomy: 21 hours, depending on the type of project.
Boom Kinematics
  • Variable Adjustable boom: 5 200 mm
  • Short arm: 2 100 mm
  • Overall weight: 19 300 kg with standard arm
Wheels and Tyres
  • Standard assembly on dual wheels
  • Type of tyres: height 10.00x20 MITAS NB38 wheels with inter-tyre bands