Re: Traction (was Re: OT: Debian Mailinglist server slow?)

[cr <cr@orcon.net.nz>]

On Wednesday 03 September 2003 21:18, Russell Shaw wrote:

> >
> > Electric traction offers a few benefits:
> >
> >   - Quieter.
> >   - Less (near zero) right-of-way (RoW) pollution.
> >   - Better high-speed performance.
> >   - Fewer ventilation issues for tunnels or enclosed operations (e.g.:
> >     RR terminals).
> >   - Ability to power all axels.
>
> The track maintenance is less with electrics because there's no
> pulsing action like with steam that pounds the tracks.

Not necessarily so.    Axle-hung (and hence unsprung) electric motors are far 
harder on the tracks than steam locomotives are.    (This would apply to any 
diesel-electrics with axle-hung motors as well, of course).     The Southern 
Railway in Britain found this out when it extended its suburban 
electrification to its main lines.   Axle-hung motors are fine at lower 
speeds but when speeds get over the 60mph mark, the track starts to suffer.

As to steam, the 'hammer-blow' is caused by the balance weights used to 
balance out the weight of the pistons in a fore-and-aft direction.    It was 
found that three- and four-cylinder steam locomotives often needed very 
little or no balance at all, and hence caused no hammer-blow.

cr