Posted by MJF on Mon Jun 23 19:17:19 2003, in response to Re: Flushing Line to B Division?,
Regarding why the older equipment takes longer to stop. The R33-36, along with the R32, 40, & 42 were retrofitted with composition brake shoes. In addition, the R33-36, which still has its original brake package, had the air inshot valve (which put the brake shoes up against the wheels as soon as the motorman applied a brake) removed. The emphasis is now on dynamic braking. Friction braking now comes in to play at the end of the braking process. Before the R33-36 through R42 were retrofitted, the motorman could enter the station and keep power applied for about 4 or 5 car lengths before he would apply the brakes, getting a harder, faster stop. Today the motorman generally shuts the master controller off as he gets to the entering end of the station and applies a brake at that point, to get the dynamic brake retardation, and continues to smooth out a stop as the friction brake comes in. This is a more time consuming process. The greater reliance on dynamic braking saves wear and tear on the brake shoes but has changed the braking dynamics, no pun intended.
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