Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site tymix.UUCP
Path: utzoo!linus!philabs!seismo!hao!hplabs!oliveb!tymix!stimac
From: stimac@tymix.UUCP (Michael Stimac)
Newsgroups: net.railroad
Subject: Diesels, MU, and double-heading steam locos
Message-ID: <156@tymix.UUCP>
Date: Wed, 21-Dec-83 13:02:42 EST
Article-I.D.: tymix.156
Posted: Wed Dec 21 13:02:42 1983
Date-Received: Fri, 23-Dec-83 04:54:24 EST
Organization: Tymshare Inc., Cupertino CA
Lines: 42

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.