Re: [Phys-l] Kinetic vs static friction

[Bernard Cleyet <bernardcleyet@redshift.com>]

Not so modern -- when I went back east W/ my father (a S'n Pacific employee) (ca 1953)  one of the trainmen (conductor or brakeman or ?) recounted the fried birds that landed on the resistor.   This was (is) for braking while descending from the mountains (rockies and Sierra Nevadas in this case).

bc has the same except the resistor is a giant battery, and thinks the equivalent for the train would occupy several freight cars.

On 2010, Nov 13, , at 21:21, LaMontagne, Bob wrote:

> Modern locomotives have what appear to be a set of wings on the rear of the lococomotive with a large grille on top of the wings. These are used for "dynamic" braking. Basically the electric drive motors are run backwards as generators/brakes sending current to a huge array of resistors under the grille. This dissipates the energy as heat.