Director of the Institute of Railway Research Simon Iwnicki gives a brief overview of the HAROLD bogie test rig at the University of Huddersfield
The HAROLD full-scale rolling contact, adhesion and braking rig is unique in combining a large 2m diameter rotating rail drum, with the capability to test a complete bogie assembly.
The rig is based around a rail drum with two circumferential rails, a bogie manipulation platform and a loading frame and actuators to allow body vertical and roll motions to be imposed through the bogie’s secondary suspension up to a maximum axle-load of 25t and running speed of 200kph.
The wheelset of the bogie under test is placed on the rail drum whilst the trailing axle is fixed to the manipulation platform. This facilitates both bogie rotation and lateral displacement relative to the rails, allowing the wheelset to be manipulated to represent various steady-state curving scenarios.
Wheelset position can also be controlled explicitly via attachment of actuators directly to the axle boxes of the test bogie. This functionality allows precise control of the lateral displacement and angle of attack of the wheelset, a key benefit when studying the details of wheel-rail interaction and contact mechanics.
The rig has the capacity to reach up to 110kNm of braking torque, this is sufficient for complete slip (wheel-slide) between wheel and rail at 25t axle-load. This allows adhesion and brake system performance (including WSP) to be investigated under realistic operating conditions. With an upgraded HAROLD 2.0 now under development, the study of traction system behaviour, dynamic braking (all-electric WSP), train brake blending strategies and hybrid drivetrain solutions will soon be added to the rig’s functionality (December 2021).
The IRR’s advanced dynamic test cell provides a high load capacity facility for mechanical static and dynamic testing applications. With a 50t capacity loading system across a fully modular test floor of
10m x 4m, the rig can accommodate a wide range of test specimens and configurations.
With the support of IRR research staff, the test rig’s state-of-the-art hardware-in-the-loop control system can be used to design novel mechanical experiments which include elements of closed-loop dynamic co-simulation or measured load profile data extracted from the operating environment of the component under test.
Within the railway sector, the rig is perfectly suited to high-cycle fatigue testing of complete trackform systems (slab and ballast) and their components. From a vehicle perspective performance of suspension components and fatigue testing of bogie frames and associated equipment are within the capabilities of the facility. These are purely examples and we welcome test application proposals from any discipline of engineering.
The specification and typical railway applications of the 50t advanced dynamic test cell are detailed below: