What kinds of bogies (trucks) are used by IRs locomotives?
For mainline BG locomotives, there were, until the 1980s, two main alternatives. The venerable WDM-2 which existed (exists) in vast numbers, along with the WDS-6, WAM-4, WAG-5, and some of the WCAM-1/2 locos used an Alco design asymmetric trimount (Co-Co) cast bogie design. Most other mainline BG locos used some variant of the GM-EMD ‘Flexicoil’ design, starting with the ‘Mark 1’ version for the WAP-1 and WAP-4 locos as well as the EMD-designed WDM-4 locos (export model SD-24), and variants known as ‘Mark 2’ or ‘Mark II’, ‘Mark 3’, etc., for other electrics such as the WAP-3. These were all cast bogies. RDSO experimented a lot with the designs of these bogies, to improve top speed, ride characteristics, etc., so that many variations can be found. The Flexicoil model was originally designed by GM-EMD and used in the American SD-7 locomotive of the 1950s. The innovation of the Flexicoil design at the time it was introduced was the isolation of lateral vibration by a swing hanger. A newer
