Tunnel Motors was [Re: Loco cab safety]

[Richard <richard_snook@primus.com.au>]

Though generally correct..the SD40T-2s and SD45T-2s (Tunnel Motors) were developed as their monicker suggests because of
tunnels, not open running!!It was found that the air intakes, roof top on most GM products were sucking in HOT air that
had migrated to the tunnels roof (as it would) thus negating the purpose of drawing in fresh cooler air. After
experimenting with "Elephant" ears and other air redirection devices some guru suddenly twigged..draw the air from low
where it isnt so hot..(wonder how much money he was on!!) Rio Grande with similar problems in tunnels such as "Moffet"
took this option on some locos as well.
Strangely this feature was included on GP15's as well..sort of making them baby-tunnel-motors.
GE and alco had not so much of a problem as their intakes were invatriably lower anyway.

You would think that with Aussie heat that this would be a major consideration when adopting imported designs...but that
might be a tad too simplistic...there is probably a very good reason for ignoring such a fundamantal and Im sure an
engineer is about to explain it!! :-)
Look at how they modified GMs for Saudi Arabian service etc..we mightnt be the Middle east but it still get s bloody hot
here..even hotter at times I might suggest.

As we taught the Americans how todesign a 3 axle Flexiciol for GMs and as they say the rest is history...maybe its time
we start listening to our own good common sense with loco design for Aussie conditions. We do pretty well but new
fangled locos should not overheat these days...its not like heat is any thing new, eh!!

Maybe a NRT-2 is the answer (little humour folks!!)

cheers >:~)) Richard


miracoil@my-deja.com wrote:
> 
> In article <8225vv$4vj13@atbhp.corpmel.bhp.com.au>,
> 
> > It could be due to the radiators or air intakes on the second unit
> getting
> > hot air exhausted from the front unit. 81s had a similar sort of
> problem in
> > single line tunnels, they moved the air intakes from the angled part
> of the
> > roof to the side of the body.
> > --
> > Regards,
> > Chris Stratton
> 
> I have no local knowledge, but I wanted to metion that similar problems
> in America resulted in a new locomotive type being developed and they
> weree nick named 'Tunnel- motors" Heavily redesigned radiators and low
> down side intakes overcome this over heating problem.
> All US GE Locomotives have massive overhanging 'awnings" radiators
> fitted. But GE Australia say they can make do with the puny systems
> fitted to NR's [ ;o)]
> 
> Sent via Deja.com http://www.deja.com/
> Before you buy.