What kinds of brake do IR’s locomotives have?

July 16, 2019, 1:26 PM
Share

Locos in India typically have air brake systems these days. As there is still a lot of freight stock, and some passenger stock that is not air-braked, many locos do have dual braking capability where they can deal with both vacuum braked and air-braked stock.

For instance, the original WDM-2 locos were vacuum-braked. As air braked stock came into wider use, many of these locos were retrofitted with air brake systems as well, hence the WDM-2A locos have dual braking capability. Later locos such as the WDM-2B and most WDM-2C units have only air brakes.

Almost all new locos (WDG-4, etc.) have only air brakes as the original equipment in most cases, although a few are now [9/01] being retrofitted with vacuum brakes because there is still a fair amount of vacuum-braked freight stock in use. The presence of air brakes or dual-braking capability is indicated by a number of ad hoc means, such as annotations (‘DB’, ‘Dual Braked’) or markings (thin blue stripes running along the bottom of a loco, for instance). The annotations ‘FP’ and ‘BP’ on a loco indicate the presence of the Feed Pipe or Brake Pipe, respectively.

Various forms of ‘dynamic’ braking are also used as supplementary systems where the kinetic energy of the loco is used to generate electricity which is dissipated in some manner (resistive grids are common (‘rheostatic braking’ or ‘dynamic braking’); some old EMUs in Bombay used electromagnets acting close to the rails; some locos used the extra energy to heat water in tanks).

In some locos dynamic brakes are part of the original equipment, whereas in others they are retrofitted, e.g., some WAP-4 locos that have had dynamic brakes with dissipation grids mounted on their roofs.

In a variant known as ‘regenerative’ braking, the energy is fed back to the overhead cables; this was done by the DC locos (WCM series, definitely WCM-1 but not all of its successors). Feeding energy back to the cables is more complex with AC power, but the latest WAP and WAG series locos do have some provision for this.

Source – IFRCA.org

Share

This entry was posted in 2 Railway Employee, STUDY NEW, Railway Employee