I see some engines will have extra air tanks mounted up on top of the hood. I assume it is to provide an extra air reserve, or larger resivoir. My question is, why do some engines have them, and others not?
Example, I see one GP35 with no tanks, (seems like most are this way) then, out of the blue, I will see one that does…
I guess, what is the reason(s) that would justify doing this modication to a engine. Thanks for any input.
[8D]
Canadian Pacific had some of their GP9s fitted for passenger service with a wider full length fuel and water tank under the frame forcing the air reservoirs to the roof.
http://www.rrpicturearchives.net/srchThumbs.aspx?srch=torpedo&Page=2
IIRC the SP engines had about the same rationale.
The other answer would be to sink “U-boats” (GE U-series locomotives) but they didn’t exist at the time.[:D]
Most typically the reason for roof mounted compressed air tanks was to make additional room available under the frame for additional fuel capacity via a bigger tank or for an additonal small tank next to the fuel tank for water when the locomotive was used in passenger service with a steam generator. This happened frequently on roads such as SOO LINE where they used their GP units in dual passenger/freight service.
Some of C&NW’s GP35’s had roof-mounted air reservoirs to make room for a larger fuel tank.
[(-D][(-D][(-D][(-D][(-D]
The Frisco used top mounted airtanks on a number of Geeps because they wanted larger fuel tanks on their locomotives. However, the Frisco had also had airtanks mounted on top of the boilers of some of their steam locomotives (e.g., 1522, if I recall correctly); although, I don’t know the reasoning behind that placement, unless it was to make the running gear more accessible for maintenance. Does anybody know?
It was my understanding as well that the air reservoirs were mounted on the roofs of units that were modified for passenger service. I remember something to the effect this was done to make room for the water tanks and sometimes larger fuel tanks. The MoPac and Central of Georgia also ran several geeps on their passenger trains with this modification.
Then of course there was the SD24 all of them had roof mounted air tanks. The Santa Fe when they rebuilt theres just spread them out.
The Santa Fe GP7s with steam generators had top mounted air tanks.
Southern E8/9’s had “torpedo tubes” to allow larger fuel tanks.
Erik
I suppose for a steam engine, putting the tanks over the boiler would keep them warm during cold weather, and keep the tanks from getting ice crystals in the air lines, although this would only work for the main tank, the train line could still ice up…
Wow, thanks alot guys for all the info… I have to admit, sheepishly[^], I bought some air tanks at my local hobby store. I thought they would look cool as some extra detail parts to put on to give my engines to give them more of a custom look. But, before I got carried away, figuered I would check. I have a SD 7 that I was considering doing. All though I really cant justify passenger service, the re-locating for larger fuel tank makes alot of sense. Hmm…[:)]
CN / GTW Geeps for passenger service had steam generators in the short hood, top mounted air reservoirs, and a water tank and a larger fuel tank in the space usually taken by the air. Came that way from EMD, so far as I recall…
If you have a fictitious line… Go for it. That’s the good part about not having to follow a prototype. I saw a log line once… I think it was up in B.C… Where they had tanks mounted on the hoods of their SWs. Apparently it was for all the extra breaking on the heavy grades. It looked kind of interesting.
Dave
http://www.dpdproductions.com
That’s the Canfor logging line here on Vancouver Island. They got 3 SW1200RS locomotives on road switcher trucks, and a plain SW1200. Three of the locomotives have had Cat engines installed, with large muflers on the roof with the tanks.
Before-
http://www.trainweb.org/rosters/CANFOR303.html
Dale,
Thanks for the links to the pictures. I guess that goes to prove there is a prototype for everything. [:D]
Cool… I was wondering if it was still around. I like the new scheme.
Dave
http://www.dpdproductions.com
Factory-installed dynamic brakes on a switcher are indeed uncommon. Coos Bay Lumber Co. had d/b equipped SW1200’s also with hood-mounted air cylinders and a larger fuel tank. UP’s TR5 sets also had d/b on the cows. LV had SW8’s with d/b but the V-8 engine allowed space for them to be mounted flush with the hood between the cab and engine.
the DMIR put the air cleaners up high on the boilers of the steamers to keep them out of the dust, had the tanks high too not sure why