Re: Modern high speed steam to Mackay.

[pierson@gone.enet.dec.com (dave pierson)]

In article <72tn9k$8hc$1@metro.ucc.usyd.edu.au>, matthew@mail.usyd.edu.au (Matthew Geier) writes...

> Been done. Many times. "ElectroDiesels' operate on the east coast of the
>US and in the UK. I think a few 'trip train' hybrids are also used in
>Europe and Sth Africa.

> The US case is due to a a NY city bylaw banning steam (& diesels) into
>the city.

	Actually, just in the tunnel.  And the ban is on combustion,
	any kind.  (Many references get the first part wrong...)

>Hence they added 3rd rail pickup shoes to an others standard
>type of diesel.

	Right.  FL9.  And AMTRAK has a few more modern ones so fitted.

> One of these types was a Co-Co due to weight problems, and it may have
>been the steam heating boiler that was the reason for the extra axle.

	The US FL9 was/is Bo-A1A, due to added length & weight of
	electric AND boiler gear.

> The british electro-diesels I think are also 3rd rail system beasts.

> Electrical wise, the low voltage DC 3rd rail power is probably feed 
>straight into the electrical part of the Diesel-Electric and the diesel
>switched off.

	More or less.  FL9 uses dynamic braking grids as control
	resistors.

> The Europen and Sth African units are severly power limited due to needing
>a step down transformer and rectifiers as well as all the usual DE junk.
>The units are basicly trip train only units - they can work into non wired
>sidings. The same railways now also have battery hybrid trip locos - they run
>off batteries into the non-wired sidings.

> An electro-diesel tilt train would have severe weight problems - it would
>need a 3000kw diesel engine AND a 25kv transformer, also rated at 3000+Kw.

	Welllll.
	A 3 MW transformer is a lot lighter than 3 MW Diesel Gen set...

	There exists a study, in some detail, done int he US during the
	'oil shock' for converting an SD40 (?) to electro diesel.  They
	found it could be done with _zero_ net weight change, by omitting
	fuel capacity.  And THAT was with dc series traction motors.
	Wheter the lighter weight of AC Induction traction motors is
	more than overbalanced by the inverters needed, for a current
	design approach, i dunno.  AND that study ws for a freigh hauler,
	not a 'high speed tilting train'.	

> In all you are probably better just building seperate DE and straight
>electric locos, and swapping at Rockie!. With diesel fuel as cheap as it
>is and no other environmental constraints, DE the whole way is quite
>cost effective.

	There's some truth to that.  Rumor has it that BC Rail may dewire
	their tunnel/coal drag section, which was wired when oil was
	$30 US/gal or whatever.  However swopping loks ALSO means having
	two seperate fllets, maintainance, capital expense...

thanks
dave pierson                        |the facts, as accurately as i can manage,
Compaq Computer Corporation         |the opinions, my own.
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Shrewsbury, Mass USA                 pierson@gone.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles
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