GE started out with a tunnel motor style radiator arrangement. They use a big fan at the top, with sucks the air from the walkway area. They didn't have the same problems. IIRC, just keeping them running at all was the trick, so they didn't get used too much in the mountains where reliability was paramount.Tunnel motors are not standard, and 20-cylinder engines aren't desirable to the UP. So many have been sold off, and 20 cyl. engines replaced with 16, in effect making a SD40-2. Saw a picture of a NREX engine. Started as a SD45T-2, but the long hood was replaced with a regular SD40-2 hood, leaving a large porch at the rear.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
Mike Lehman
Urbana, IL
Great help! Thanks all.
Now to find one!
Hi Dave. The tunnel motors weren't designed / re-arranged to breathe in tunnels. Rather, they were designed to cool down faster between tunnels. The common mis-understanding is that the lower air vents was to take in air down low in the tunnels where it was supposedly cooler. An EMD design and sales engineer who had worked on designing the tunnel motors set the record straight in an issue of Trains mag backabout 4 years ago. He mentioned that tunnels are such a small cavity, that all the air in a tunnel gets hot fast when a hard working loco passes through it. The cooling system was designed to cool the engines down faster after they get out of the tunnel and before they go into the next tunnel on mountain grades with lots of tunnels (think Donner). This option was priced at a premium, thus the RR's had to really determine whether or not their operaing conditions warranted / offset the higher cost of such locos. Only the SP and Rio Grande thought it a worthwhile investment for their conditions, and ponied up the cash to buy them new. Like what the other posters said, the newer or later models have better / more efficient cooling systems from the advancements in technology negating the need for premium priced specialized tunnel locos. Hope this helps.
Greg
Southern Pacific and Cotton Belt Tunnel motors were free runners. They were assigned, but not confined to the mountains. I have a photo of a brand new tunnel motor in Commerce, TEXAS on the Cotton Belt dated 8-29-72. As the new Cotton Belt tunnel motors were delivered in the spring of '73 they would often show up in Commerce. I have photos of the tunnel motors in Commerce, TEXAS and Houston from 1973. Espee and Cotton Belt owned a combined 247 SD45T-2s and 239 SD40T-2s. Cotton Belt owned 94 tunnel motors overall and had no tunnels!
Dave-the-Train wrote: Also... when did the Tunnel Motors start escaping from the tunnels into the flat lands please? They are a nice variation on the theme but (so far) I have behaved myself and not added one to my roster in the belief that in the 1980s they wouldn't have strayed from specialist service as far as Chicago(ish). TIA
Also... when did the Tunnel Motors start escaping from the tunnels into the flat lands please?
They are a nice variation on the theme but (so far) I have behaved myself and not added one to my roster in the belief that in the 1980s they wouldn't have strayed from specialist service as far as Chicago(ish).
TIA
Dave,
The 40 series EMD locos had cooling problems, period. There are a SD40T-2's as well. The cooling problems were resolved in later Series (50's 60's etc) with larger, higher capacity radiators and cooling systems, hence no need for the tunnel motor configuration. They never really "strayed" from service, since the additional cooling was needed in other areas, like California's central valley in the summer.
And they do make nice additions to a roster, especially the Athearn RTR units that you can actually see through. So....get one, better yet get two, they usually ran in pairs.
Tilden
SD45Ts were tunnel motor variants re-arranged so that they could breathe in tunnels... so why aren't there SD50Ts, SD60Ts, AC whatever Ts and GE equivalents?