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. 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. Would SD7 or maybe GE U30 be a feasable for extra tanks?[:)]Thanks for any input.
[8D]
Usually this was done on engines that were set up for passenger service. They would add a steam generator to supply steam heat to the passenger cars. This necessiated a water tank for the generator, which was added next to the fuel tank. All this left no room for underbody air tanks, so up to the roof they went.
Adding to the above, in most cases they did not increase the air capacity per se. An exception is the SR’s E8.
SD7 - not likely, U30 definitely not. Roof top air tanks were common on SD24, but not the torpedo tube configuration.
Can’t say for sure about other RR’s but on the SLSF, the GP35’s that had the air tanks mounted on the roof, (torpedo tubes). These are not extra but were moved there because of the extra large fuel tanks.
Vampire and tigerstripe are bothe correct. In early days of dieselization, some
GP7s and 9s were equipped with steam generators. To provide adequate
water tankage, the air reservoirs were moved to the roof. Later, certain
roads wanted units with increased fuel capacity, and thus relocated the
tanks to the roof. Frisco, for one, had GP35s configured this way.
Thanks for the replies guys. I admit, I really cant justify the tanks for passenger service, but the idea of being moved due to increased fuel tank makes alot of sense. Heck, I have even done that in the real world. (working 4x4’s, not trains). OK, so GE is out… but the SD7… hmmmm… I do have some long grades in my territory, burns up alot of fuel on some “heavy” days… I think I might have to submit a plan to managment.
[:D]
Southern Railway didn’t mount their E8 air tanks on the roof for extra air capacity, it was because they needed extra water capacity. So, it would be appropriate for passenger power.
Brad
Forget all that stuff they told you earlier. They actually WERE torpedo tubes. The U-Boats had them, so some railroads fitted their locomotives with them. They were called PT boats. [;)]
Plus engines kept the ‘tubes’ long after passenger service ended - some CNW GP’s had them into the eighties, a few highnose Soo GP-9’s made it into CP red in the nineties with them still up there !!
Air tanks ended up on top of locomotives whenever there was no room in the ‘customary’ place(s) to put them. And they were not restricted to diesels.
The Mantua 2-6-6-2T, like its Uintah Ry. prototype, has its air tanks topside, because the side tanks fill the space where they would ordinarily be mounted. The same thing happened with a lot of tank locos in Japan when that country switched over to Westinghouse brakes in the 1930’s.
Since the space under the running boards was full of steam plumbing, the air tanks on the Allegheny 2-6-6-6 ended up on top of the firebox and combustion chamber.
Chuck
Here you go canazar, a prime example of roof tanks, SP GP-9 with steam gen. in nose, larger tank for fuel\water, hence air tanks moved to the roof.
FWIW DM&IR 2-8-2’s had tanks mounted on the boiler. Think they needed extra air for brake lines with those long strings of ore cars ??