rail traction resistors

Locomotive Testing

traction-locomotive01DC7000 load banks
for locos up to 4000 HP

A purpose-built load bank for the performance testing of engines and generators of all types of diesel electric locomotive up to 4000hp rating, with easy-to-use resistance adjustments allowing tests to be carried out over the whole power envelope. Capacity 0 – 7000A continuously at up to 2000V DC


Setting of the required load resistance is fully automated through 20 motorised and plc-controlled off-load switches, with all settings and test parameters monitored and recorded on the separate control panel. An optional manual control system is also available.


The load consists of twin fan-cooled resistor ducts with fans, starters and controls, two main load isolating contactors and an integrated off-load switch panel permitting the pre-selection of any one of more than 200 values of resistance between 0.026 Ohm and 3.3 Ohm. The fans, resistors and switchgear are all built in to a single sheet steel frame with hinged lockable access doors, air intake screens and (optionally) hand-operated outlet louvres. Paint finish is RAL7032 light grey powder coat. The enclosure is designed for floor mounting with bottom cable entry. Fan motor and control voltages are set to suit the user’s own available supply voltage and frequency.

 Cressall's DC7000 load bank trackside testing Freightliner 66 Heavy Haul 3300hp diesel loco

Cressall’s DC7000 load bank trackside testing Freightliner 66 Heavy Haul 3300hp diesel loco

Resistor elements

Type EN650 traction resistor elements, arranged in individually replaceable banks with all-welded interconnections. Each bank is contained in a fully insulated duct section with two independent levels of 3kV electrical insulation.

Resistor material

The resistor elements are manufactured from Inco alloy 601, a 60:23 nickel-chrome stainless steel. This is a high-grade stainless steel with excellent corrosion resistance properties and a low (0.04%/°C) temperature coefficient of resistance, giving very stable resistance values over the whole range of operation.

Connection scheme

The off-load switches allow for the reconnection of the resistors in each stack into more than 200 different configurations with a range from .026 Ohm/7000A through to 3.25 Ohm/600A. There are intermediate points to suit the majority of loco alternators up to 4000hp rating.

Download: DC7000 Datasheet