Hello, I would like to know if the FP7 was used in solo for freight or passenger cars or was the B unit always in back of the main engine at all times ?
Thank you.
Either would have been seen in real life, but an FP7 would have most likely been coupled to another FP7 back to back, or to one or more F7 or F3 B units. For example, the California Zephyr was pulled by an FP7A followed by 2 B units, usually and F7B/F3B or two F3B’s. Southern Pacific would have probably had F7B units couple to their FP7A units.
CPR commonly used a single FP7, or other A-units (FP9, FPA-2) on shorter passenger trains, say up to about 6 cars. Through freights generally needed more than one unit to haul the tonnage, so single units, and especially cab units, were uncommon but it did occasionally happen. While additional units might be B-units, any road engine could be used instead. Many road switchers had through steam lines even if they didn’t have a steam generator so they could easily be used in passenger service.
John
Hello John and Riogrande, thank your for the infos on the “B” unit ; it’s very much appreciated.
I have a small layout (10x12), so I think a “B” unit will not be required with the FP7 because it will be pulling only 7 or 8 cars at a time.
Have a great day [:)]
The answer to your question varies depending on the prototype road in question. For example, Atlantic Coast Line purchased 44 FP7 units, the second largest amount in the U.S. What’s interesting is no booster units were ordered to complement them (ACL had B units on the roster - F2Bs, F3Bs and F7Bs).
They were used as passenger power on local and connecting trains and on mainline freight trains; in passenger duty you could find a single unit or a pair of them depending on the length of the train and whether or not there were any grades on the route. In freight service it was common to find them in a consist mixed with GP7s and F2/F3/F7 cab units.
During the 1950s and 1960s they could serve as protection power for the premier trains (East Coast Champion, West Coast Champion, The Everglades, Havana Special, etc). In later life, a good number of them had their steam generators removed and the converted units served strictly as freight power.
Hello Carl, thank you for the additional infos [tup], the’re greatly appreciated.
There is no requirement to run an F7B with an FP7(A), or even an FP7(A) with an F7B. Either type can run with any other type of engine. The only caveats are:
-
since the B unit has no cab, it can’t be used by itself or lead (there are controls to be able to move it by itself in an engine facility, but it can’t be alone on a train)
-
some railroads (like CP) had their F-units delivered with no MU connections on the nose, so the FP7A unit cannot be nose-coupled in the middle of a consist. However, other railroads did have nose MU connections, whether at delivery or installed later, so that wouldn’t be an issue for that railroad.
A lot of modellers seem obsessed with running “pure” matched A-A, A-B, A-B-A, A-B-B-A, etc. sets when most railroads did not keep sets together like that.
Case in point:
http://members.fortunecity.com/rrpics/cpfunits/cp4459.jpg
http://members.fortunecity.com/rrpics/cpfunits/cp1412.jpg
Here’s a nice mixed consist on my club’s layout which is totally typical of the time period:
Modelers are obsessed with running matched sets because it is how how they appear in the pictures and it looks really cool. When you talk about what most railroads do, its best to check typical practices and time periods.
In the case of the D&RGW, throughout the 1940’s it was mostly ABBA freight sets and depending on passenger train, ABBA sets or AB or ABB sets for shorter passenger trains. Starting in the late 1950’s D&RGW began splicing ABBA sets with GP9’s, but passenger power followed the same pattern - ABBA sets for the California Zephyr. During end of F unit operation on the D&RGW, all bets were off for everything using F units except the California Zephyr. Helper units could be up to 8 or 9 F units strung together mixed with GP9 or SD9 units, and head end power could be 3 to 5 units of F’s usually. The Cal Zeph would run with minimum ABBA sets and in summer when expanded consister were run it could be an ABBBA or ABBBBA set!
Hello, you guys are right about the manufacturers wanting to sell both A and B units because it looks good on display; that’s why I posted this topic to get additional infos on the subject and once again I thank you for your feedbacks. Now I wont be shy to run my FP7 unit alone with a few cars…
HAVE A NICE DAY…
You certainly can run FP7A’s by themself. In fact the reason why FP7A’s were designed and built was so that a single diesel could pull a passenger train and provide steam heat. While the D&RGW didn’t own any FP7A’s, they did purchase two F7A’s equipped with steam generators as part of an ABBA set. Functionally they were the same as the FP7A’s except they had a limited capacity due to lack of space for the water tanks. The FP7A’s were simply F7A’s stretched by about 4 feet to provide space for a more usable capacity of water storage so that a single locomotive could have a good range and time between refills.
Rio Grande ostensibly ordered their two steam generator equipped F7A’s to provide them the option of running single diesels in passenger service if needed. In fact, in the 1960’s, there are photo’s of the Yampa Valley Mail, a two car passenger train led by single diesels. However, the two steam generator equipped F7A’s had lost their boilers in the early 1950’s, long before the those photo’s were taken. I suspect the 2 car Yampa Valley Mail trains led by a single F7A or PA were were photographed in summer when steam heat was not needed, otherwise you usually saw a SG equipped B unit behind the F7A or PA unit.
Interestingly, those two D&RGW F7A’s #5571 and 5574, are among the few examples of prototypes which match the old Athearn Globe F7A shell - noting it is an “phase I” style F7A body but has steam generator details on the rear of the roof. I believe either Great Northern or the Northern Pacific also order a few F7A’s which were like this (essentially “short FP7A’s”. Since Athearns Globe F7A was for many years, the only “decent” HO model of this diesel commonly available, I am amazed they didn’t tool it without steam generator roof details since that was the universal F7A. Otherwise the modeler is forced to carefully shave those off, which I did in the 1970’s and it took a lot of work to do that while leaving the s
Generally railroads that ordered FP’s did so either because they needed lots of steam heat (like the Canadian railroads) since a standard say F7A didn’t have much room for water storage, so usually didn’t have a steam generator, or because the railroad had short to medium length local trains that required a decent amount of steam heat but not enough to warrant using both an A and a B unit - say a train going 200 miles or so and only having 3-4-5 cars.
On flat territory (non-mountainous) one FP with 6-7 cars as you describe should be fine. Note that trains weren’t always the same length, a train that had 3 cars on a weekday might have twice that many on a weekend. You could set a limit for the FP so that if you decided to run more than X number of cars, you’d have to add a second unit.
Hello Stix and Riogrande thank you for the additional infos on the use of the FP7 by the railway companies.
I totally forgot that the FP series were built a little longer because they added the steam generator inside the engine, thus eliminating the need for the B units on short runs with few cars.
Not exactly a “few” on the GN–all their passenger F’s had boilers, both A’s and B’s. I count 115 total–about half being A’s. Plus there were 3 Alco FAB-1 sets, too. I just checked some NP photos, and it looks like they usually had boilers in their F-unit A’s also.
Ed
I bought the Athearn Genesis Cotton Belt FP7 because the price was right and my second modeling choice is the Southern Pacific. I did some research to find which B unit the Cotton Belt paired with it. Well come to find out they did not pair a B unit with it but ran it solo.
Ed, Joseph Strapac in Rio Grande Diesels mentioned as an aside regarding the F7A with boilers that the northern RR’s had these. The point being that it was very unusual to have boilers in standard F7A’s nationwide. If Great Northern had boilers in roughly 60 F7A units, that is a probably the lions share EMD produced so equipped.
F7B units equipped with boilers as a rule were far more common than F7A’s. In contrast D&RGW had 152 F units if I counted correctly (FT, F3, F5, F7 and F9’s) and approximately half were B units. Of the A units only 2 had boilers, of the B units, IIRC 20 had boilers. (2 FTB,s, 6 F3B’s, 8 F7B’s and 4 F9B’s).
I agree that most FxA’s didn’t have boilers. That also applies to the B-units, I think. It’s just that I keep hearing on this and other forums that NO FxA’s had boilers–only the B’s did. Well, on the Santa Fe, that might have been true. On the WP, ALL passenger FxA’s had boilers–all 3 of them. I know that WP soon went with the FP’s instead of more FxA’s. On the NP, I count 44 (all of them); and on the SP&S, I count 7 (all of them).
So, while GN appears to have had the largest fleet of FxA’s with boilers, it wasn’t really the lion’s share of EMD’s production, as the combination of Rio Grande, WP, NP and SP&S pretty much equals GN’s fleet size.
I do wonder if anyone else got boilers in their passenger FxA’s.
Ed
It would be interesting to see of the total FxA units and FxB unit, how many were produced with steam generators. My guess is the more than half of B units were without steam generators, probably between 60 and 70%. A units much less so. I’ve never read on any forums people claiming that F3A or F7A or F9A units never had steam generators.
Joseph Strapac commented in my book that it was primarily the northern RR’s which added steam generators to their FxA orders from EMD. That is consistant with your figures and findings.
I used to wonder why Athearn Globe chose the F7A with a SG but I guess there were enough A units out there with them and Athearn was biased to western roads. I don’t think as many eastern roads used steam generators in A units.
Actually the problem with regular F units was that although you could put a boiler inside the A unit, you were very limited in space to put the water to boil. The added length of the FP series was primarily to add space for water. I forget the exact numbers but I think an FP7 could hold 3-4 times the amount of water than a regular F7A.
NP had some baggage cars that had large water tanks inside, that could be connected to the engines.
Yes. I think I already pointed out this detail above in my earlier posts. It was the lack of space for water capacity. I already noted there were standard body F7A’s with steam generators so that was covered clearly enough. Of course why have a steam generator if you don’t have water to boil? It was always a capacity issue and why the FP7A’s had something like 4 feet added to the bodies to provide room for the additional water.
Modelling was a lot less precise back then of course, I think Globe / Athearn may have figured if they were going to put the generator stack etc. on the B unit it would be easier to do it on the A shell too…or maybe they just thought it looked neat. [;)] Adding the steam generator stuff made the model look more “detailed” even if it was (for the most part) unprototypical.