I have some questions regarding F7 operations. I know that the FP7 is 4’ longer than a F7 and that the extra real estate is for the steam generator. My questions are:
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[] What us the purpose of the steam generator?
[] Do passenger trains ever run with a combination of F7s and FP7s?
[] If they can be run in combination, Does one or the other have to be on the lead?
[] Do passenger trains ever run with just F7s? (if yes, which railroad companies did this?)
[] Were there ever F7 B units built?
[] Was there ever any FP3s?
[/list]
The extra 4’ in an FP7 is for an extra water tank. NOT for the steam generator.
The steam generator is used to supply steam line heating to the passenger cars.
Some roads did run F7’s and FP7’s together.
Either one can lead.
Many companies used F7’s in passenger trains. (some used FP7’s for freight or dual service)
Lots of F7B’s were built. With and without steam generators. There were no FP7B’s built. FP7’s and FP9’s were run with regular F7B’s and F9B’s. Because there was no cab, there was lots of room inside for additional water capacity.
Concerning the Santa Fe, only the F7 B units had steam generators. The steam was used for both heating and air conditioning (steam ejector AC) on their passenger trains. Later on the Santa Fe built some steam generator cars at their Topeka shops using ACF baggage car bodies (don’t know why I threw that in there, but I did).
Some of the F3,7A units had steam controls so they could operate passenger trains as long as there was a steam-equipped B (cabless) unit along with it. The SP had steam controls in some F units as well as having FP-7s, so either of those could lead passenger trains. Usually those steam-control F units as well as boiler equipped GP-9s, SD-7s, and SD-9s were used by the SP as stand-by passenger units, but they were mostly used as freight locomotives. All the boiler-equipped FPs, GP-9s, SD-7s and SD-9s had water tanks. When the road switchers had their boilers removed, the water tanks were converted to carry diesel fuel.
It was the FP_9_ that was 4’ longer to accomodate the steam generator for passenger service. Trying to find a manufacturer with a prototypical FP9 is like trying to win the state lottery. Your better off building your own from resin kit and GP38 drive unit.
B&M ran FP7 and FP9 I believe. I know that CN ran FP9’s, and the Conway Scenic RR in New Hampshire has an FP9.
The FPs did have steam generators. The four extra feet was to provide room for a water tank. If the locomotive was not lengthened, the fuel tank’s capacity would be further reduced.
F something A-units and F something B-units had the area immediately at the rear of the carbody available for the installation of a steam generator and a number of roads ordered their covered wagons so equiped; A-units had restricted water capacity but B-units, on the other hand did not have the restricted water capacity of an A-unit because the area where the cab would normally have been provided adequate space for a water tank. These B-units had through piping to transit steam from the A-unit to the remainder of the train.
Sometime in the early '50s EMD overcame this A-unit’s restricted water capacity by splicing a four foot section into the unit immediately to the rear of the cab and installing a water tank in the area created; the subsequent FP7 and FP9 had, effectively, the same steam generator capacity - or nearly so, anyway - as an A/B set combination and were intended for sale to roads which did not wish to purchase steam generator equipped B-units. There were, some roads, however, which opted to purchase not only the FP but F something A-units and F something B-units equipped with steam generators.
Note: to the best of my knowledge no FP9s were ever sold to United States carriers; the next time
The F2A through F9A could have a S/G in the rear compartment. Usually there was 200-300 gallons of water in the S/G unit. This would be exhausted very fast in cold weather. If the railroad did not need S/B equipment, a 600 gallon ‘hatch’ tank could be installed in it’s place. I am not aware of any F unit that had underbelly water tanks(but there might have been some). The underbelly package consisted of a 1200 gallon fuel tank, with a pair of battery boxes just forward of the fuel tank. The air tanks were between the battery boxes - rather limited space under there.
The Santa Fe did not have S/G boilers in the A units - there was a 1200 water tank there, and since they needed D/B’s, there was not hatch tank. There was special pumping equipment to move that 1200 gallons of boiler water back to the B units(which had a 1200 gallon tank as well).
The GN bought ABA sets of F3 and F7 engines with no D/B’s, and the 600 gallon hatch tanks. Without D/B’s, they usually had to stop at theo bottm of Walton Hill to let the wheels/brake shoes cool down.
The NP bought ABB sets of F3’s for their transcon trains - with D/B’s and the 1200 gallon tanks in the boosters. And the NP even had ‘water-baggage’ cars to supply additional boiler water! In -25 below winters, the S/G’s could burn up diesel fuel and boiler water very fast.
The FP7 was built at the request of the Rock Island, and could carry at least 1950 gallons of boiler water, and still have D/B equipment. They could also have a 600 gallon tank hung underneath in front of the battery boxes. The closest American FP9 was the C&NW FP9m engines that were built using some trade-in parts from FT’s and looked like FP9’s, but only had 1500 hp.
When I worked for the CB&Q in the late 60’s, the E8 and E9 engines had 1950 gall
Thanks everyone for the education. I’m quite a bit smarter on the subject than I was before I started this thread a few short hours ago. I hope I can return the favor someday.
Not only on their F3’s, but also on one of their 4 F2’s, and several of their E8’s as well. Of Southern’s 102 F3A units (excluding the F5’s), nearly all were rebuilt in the mid-50’s to F7 ratings, had dynamic brakes added, and many had larger 1,225 gallon water tanks installed. These had the air tanks roof mounted. Of Southern’s 19 E-8’s, the 7 of them which were not assigned to subsidiaries had air tanks roof mounted, and 1,800 gallon water tanks added, along with dynamic brakes. This was in the late '50’s.
The FP’s were as follows: FP7, 297 sold in U.S., 57 Canada, 18 Mexico, 372 total. FP9, 4 U.S. (to C&NW, rebuilt from FT’s, rated 1500 HP), 54 Canada, 25 Mexico, 83 total. All were A units, no FP B units were built. All FP’s were 4 foot longer cousins of their corresponding F unit relatives, thus the FP7 and FP9 were the same length. The FL9 was 4 feet longer than the FP9 (8 feet longer than an F9), but had a 5 axle arrangement Only the NH had these, there were 60 of them.
GM’s design for F units, going all the way back to the first FT demonstrators in 1939, was that water and steam generators would only go in the B units. Not having cabs, they had the room in there. It was possible (and later did happen) that you could shoehorn a steam generator and water supply in an A unit, but it wasn’t easy. The FP allowed railroads to run a local train with a single unit (for example NP used their FP’s on 4-5 car locals in northern MN) or together with B units with generators/water to provide more steam when needed (hence the FP’s popularity in cold Canada).