Capable of pulling 500 tonnes, the E4 has twice the pulling-power of its smaller cousin, the 250 tonne capacity Rotrac E2 that made its debut last year.
Using Linde drive technology, unique in the railway technology sector, the small electric rail trolleys can shunt trailers and freight trains in the tightest spaces, making them ideal for tri-modal use in ports, loading stations and shunting operations.
With the Rotrac E2, the amount of torque generated by the electric four-wheel drive and the adjustable contact pressure on the rails due to its moving guide rollers, means that it can tow 250 tonnes without difficulty. When off the rails, the electric four-wheel/live-axle steering enables it to manoeuvre freely on asphalt with a turning radius of only 0.9 metres.
The Rotrac E4 uses the same drive concept from the E2 with the addition of turntable steering for travel alongside the rails. It can be extended for ground travel, whereby the rear axle is raised off the ground, allowing the vehicle to be driven using only the front axle for easier manoeuvrability and enabling it to turn on a radius of less than two metres.
The innovative drive concept was achieved by using serial equipment from heavy trucks manufactured by Linde, using two AE 18-05 48 V drive axles (2 x 4.5 kW S2-60) with an AC S10 48V converter. The regulated braking characteristics allow for high levels of energy re-covery through recuperation. Zwiehoff uses a 48 V/420 Ah traction battery as an energy storage device; the removable battery is sufficient for one shift.
Production of the units is at Linde’s subsidiary Proplan, with Zwiehoff supplying the vehicles around the globe, including Australia, Kazakhstan and Brazil.