stimac@tymix.UUCP (Michael Stimac) (12/21/83)
A couple of notes relating to the operation of diesel-electric
locomotives (see how easy it is when we call things by the correct
name? :-) ):
*) 99+% of 'diesels' are diesel-electrics as many respondents have
already mentioned.
*) a few diesels are diesel-hydraulic (transmission). One example
was the Krauss-Maffei diesels built for Southern Pacific and the
Rio Grande. The RG liked them, and the SP did not. This type is
still fairly popular in Germany, I understand.
*) until Electro-Motive Corporation showed the way, many unsuccessful
attempts were made to run straight diesel power with mechanical
transmission. In general, this did not work, for the reasons already
mentioned. EMC was later bought by General Motors, and became the
Electro-Motive Division of GM. Early diesels have EMC builder plates.
*) one respondent suggested that, although electrics and diesel
electrics could be MU'd, steam locomotives could not be, and were
not, "ganged". This is not true, steam locomotivees were routinely
and frequently "ganged" - "double-headed" or "tripled-headed" being
the proper expression. While steam locos had no MU control provision
to permit operation of multiple engines by one engineer, they could
and DID double-head engines by having cooperating engineers in
the several locomotives. This required a great deal of finesse on
the part of the engineers, and was often accompanied by a great
deal of slipping and re-starting. An extra engine on the front
of the train was often referred to as a "helper" ("snapper" on the
Pennsylvania RR) while one on the rear of the train was called a
"pusher". Much whistle-blowing accompanied the starting or stopping
of a train that had one or more pusher engines, as the respective
engineers sought to synchronize their application of power. The
Pennsylvania RR (the one I'm most familiar with) ran heavy freight
trains up and around Horseshoe Curve with 2 I-1 class on the head
end and 2 more I-1s on the rear. At the crest of the hill, the
extra engines would uncouple and run back down to be ready to help
assist the next freighter - in those days not a long wait.
I could talk about I-1s, but this note is long enough as it is.ntt@dciem.UUCP (Mark Brader) (12/23/83)
I'd like to point out a couple of diesels that are not diesel-electric. Budd RDCs need no introduction around here, but I don't know about you, so I'll say that they are multiple-unit railcars, which are widely used in Canada (usually in sets of from 1 to 3) on routes that can't support a locomotive-hauled passenger train (financially, I mean), but are not yet ready to be abandoned. And RDCs are diesel-hydraulic, not diesel-electric. (I don't know exactly how the transmission works, though; the driver's control simply has a linear sequence of positions, high being used from rest up to full speed, and no shifting is perceived as in a car.) On British Rail, there are also a lot of multiple-unit trains on minor passenger routes, but in some parts of the country these are diesel-mechanical. Here the gear shifting is very noticeable; the motor seems to spend as long slowing down during the shifts from 1st to 2nd and from 2nd to 3rd as it does accelerating the train in 1st and 2nd! I presume the reason BR has these units is that they were cheap to build. Mark Brader, NTT Systems Inc., Toronto
burton@fortune.UUCP (Philip Burton) (12/28/83)
Yeah, let's talk about them.
--
Phil Burton, Fortune Systems:
-- 101 Twin Dolphin Drive, Redwood City, CA 94065
-- (415) 595-8444 x526
-- {allegra,amd70,cbosgd,dsd,floyd,harpo,hollywood,hpda,ihnp4,
magic,megatest,nsc,oliveb,sri-unix,twg,varian,VisiA,wdl1}
!fortune!burton