I have got some F3A, F3B, F7A and F7B. How can i mix and match that engines from point of view of technical capabilities?
Another question is how did NYC mix and match that engines?
Reinhard
Many railroads bought F units in two-unit sets, either A-A or more commonly A-B; sometimes with a drawbar between the two and sometimes regular couplers. (FT's were originally designed to only be available in A-B sets with a drawbar between the two.) Often they bought sets to run together, treating an A-B-B-A set as one locomotive. However, most railroads realized pretty soon that there was an advantage to be able to mix and match engines to get the right horsepower for different situations, so set it up so their A and B units could all be mixed together.
So seeing an A-B-B-A lashup of an F3 A-B set and an F7 A-B set would be normal, but it might also be a mixed bag - F3A-F7B-F3B-F9A for example. Some railroads didn't put m.u. connections on the nose of their cab F-units (like Soo Line) so A units could only be found at the end. Otherwise other roads would mix A and B units together. NP used to use an A-B-A set of F units on the North Coast Limited in the flatter country of MN-ND-Montana, then add a third A unit for the mountains, so A-A-B-A lashups were common.
F units are essentially interchangeable (except for FT's which came as semipermanently couple AB sets).
Looking at the F unit pix in Sweetland's "Lightning Stripes", F units were mixed interchangeably with GP7's/GP9's
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
More examples from a non NYC RR.
Rio Grande purchased nearly all of there FT's F3's F7's and F9's in ABBA sets. Only two F7 sets were bought ABA and then later filled out to ABBA sets with 2 extra F9 B units.
Some of Rio Grande's FT's were delivered with draw bars and some with couplers between the A and B unit. So not all FT's were drawbarred together.
Rio Grande ran the F's mostly in ABBA sets in freight service during the first 10-15 years. A few F's were ran in AB sets in passenger service or rarely freight. In the late 50's and early 1960's, Al Pearlman, who incidentally later ran the NYC, began making up power sets for freight trains on the D&RGW using F7AB-GP7-F7BA sets. They were coined Pearlmen Mallets. By the mid-1960's as hood units were taking over in numbers, F units were cobbled together in all and any combination to get enough power to get heavier trains over the summits at Tennesee Pass and Soldier Summit. You might see and ABABA set on the front and and ABABBB-GP9 set mid-train. Quite fascinating to watch on the DVD set Rio Grande Odyssey.
As for mixing FT F3 F7 and F9's, it wasn't taboo, but as it turns out, mostly it didn't happen. FT's were kept together. There were only 3 F3ABBA sets which were used virtually their entire lives for passenger only service. Only during the last year or two of operation could they be seen with F7's or F9's. I've seen maybe one F3AB-F9B-F3BA set, and in the last 4 months before retirement an F3AB-F7BA set pulling the California Zephyr. F9's and F7's were mixed freely.
Rio Grande. The Action Road - Focus 1977-1983
A lot of railroads found that three FT's would be "just right" for freight service, but they were originally only available in A-B sets with drawbars (there wasn't even a door between the A and B units - if you disconnected the two, one end would be open to the elements) and one A-B set didn't have enough power, and a full A-B+B-A consist had more than needed. Some railroads did make special orders for FT A-B-A sets using a special short B unit (the FTSB) from EMD, but right after WW2 many roads bought F2 or phase 1 F3 A units to make an A-B-A lash-up with one FT A-B set and one F2 or F3. Not sure if NYC did this or not??
csmith9474 wrote:I could have sworn that I read somewhere that F3s could not lead F7s or vice versa. This was in regards to Santa Fe running practices. I think it had something to do with MU controls. Maybe somebody could correct me on this or verify this info??
That might have been something specific to Santa Fe units?? Maybe they had some F3's that didn't have m.u. connections in the 'nose' of the A units so they had to be in front or something?? It wasn't uncommon that railroads ordered cab F units without m.u. connections in the front, only in the rear to connect to a B unit.
wjstix wrote: csmith9474 wrote:I could have sworn that I read somewhere that F3s could not lead F7s or vice versa. This was in regards to Santa Fe running practices. I think it had something to do with MU controls. Maybe somebody could correct me on this or verify this info??That might have been something specific to Santa Fe units?? Maybe they had some F3's that didn't have m.u. connections in the 'nose' of the A units so they had to be in front or something?? It wasn't uncommon that railroads ordered cab F units without m.u. connections in the front, only in the rear to connect to a B unit.
I think you are on to something there. I do believe that it was specifically in regards to an A leading an A. I am going to have to try to dig something up on this.
Read somewhere that the mu voltage of F7/F9:s would fry a F3/FT:s mu if the F3/FT was not rebuilt to handle the F7/F9:s higher mu steering voltage. Local rebuildings and also a "kit" from the manufacturer alleviated the problem pretty early on. F3/FT:s could however be controlling F7/F9:s since the problem only occured when a F7/F9 was in the lead.
Greetings Hans from Sweden
Reinhard,
I have an New York Central DVD showing footage of a couple of F7s(?) being consisted with some Geeps. (The Geeps are in the inside with the F7s on either end.) It was very strange looking to see, to say the least.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
In the mean time I got the "Enginemen's Operating Manual Model F7" from EMD.
It says in §330 that FT, F2, F3 and F7 can be mixed as you like.
That follows a list of conditions to be met or to be observed. e.g. same gear ratio, transition indicator of leading F7 does not show correct values for trailing F3 etc.
From point of view of us modell railroaders we can mix and match as we like!
Thank you all so much for your help
Hi,
I agree with the previous postings, in that as long as the gearing matched up - and the MU connections were ok - then pretty much anything goes. Growing up in Chicago I saw a lot of this in the '50s-'60s with several different roads, and not only with F units, but with GP/SD units too, all mixed together!
Having said that, I really have a hard time having a consist on my ATSF layout that is mixed up, as the asthetics just don't look right to me. And yet I fully realize - that except perhaps for name trains - the prototype RRs really didn't care what locos they used, just so long as the power was appropriate. But, IMHO, they just don't look as nice as the "same unit, same paint scheme" consists.
FWIW.......
Mobilman44
ENJOY !
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
ndbprr wrote:I remember what it was now. The F3 engines had a lower amperage traction motor rating then the F7s. So when watching the ammeter when running an F7 if there was an F3 in the consist it could be burning up the traction motors. I suspect that eventually they were all replaced with the newer version but until they were this was a potential problem.
I do recall that this was a problem that was discovered early on in the game, and was "fixed" over time.
I'm not a expert on this, but aren't B Units simply a locomotive without a cab. If that's the case, all things being equal as mentioned about gear ratio's, a B Unit should run with any other locomotive, just like running an SD-40 with a C 40-8. If not, why not?
Ray
rayw46 wrote: I'm not a expert on this, but aren't B Units simply a locomotive without a cab. If that's the case, all things being equal as mentioned about gear ratio's, a B Unit should run with any other locomotive, just like running an SD-40 with a C 40-8. If not, why not?Ray
Yes that's not a problem, I've seen pics of a GP-F7B lash-up. Well except that some early F units were purchased in A-B sets with a drawbar between the two, so they always had to run together. Most railroads later replaced the drawbars with couplers so the A and B units could be put in separate consists, or one could go to the shops while the other kept running.
BTW it wasn't unusual to see a long train with engines from two or three different manufacturers m.u.'ed together in the fifties-sixties.
On the prototype, even the gear ratios did not have to match. Since every powered axle had its own independent motor, locomotives of different gear ratios could run together, anf they would synchronize.
What an engineer had to be aware of, though, was the traction motor ratings for the various units so he wouldn't overload either load or speed ratings (in theory, anyway - I found out that if a chief dispatcher tells you you have all the power you need, he's the expert and there's no way an engineer can burn up a traction motor, no matter how much amperage it pulls.
SHABBONA_RR
There were differences in locomotive control schemes that caused problems at first. Through the F3 model, the transitions were all manual. With the advent of the F7 model, transitions became automatic. Trying to use an automatic cab with a manual transition booster could cause problems because the older booster didn't speak the control language of the newer cab. But eventually the older units were fitted with controls that were interchangeable.
Some FT units in later units were regeared and ballasted with concrete for use in drag service in combination with newer units. This was done because as they were originally built they couldn't use their full horsepower at the slower speeds the newer units were capable of. But with regearing and extra ballast there was new life in old units. As long as the prime movers were in good shape life was good.
I have photos of all kinds of curious power combinations including rather amazing assortments of geeps with a cab unit booster thrown in the works for good measure. One I remember well was a photo of a GP40 coupled to a GP7, one unit being exactly twice the horsepower of the other. Again, the combinations were almost limitless and there were only a few combinations that couldn't be made to work together. Baldwin units had pneumatically controlled MU interfaces and they couldn't be used with those that had electrical interfaces, so that would be a no-no unless the Baldwins were used as a tail end pusher or something like that. But otherwise, the only rule was if it works for you, try it. I find it fascinating to see the interesting combinations that appeared over the years and I like to model these in my own private world.
One combination on the Union Pacific that got quite a bit of useage was putting an E8 or E9 A unit with a F9 B unit to make a locomotive with a total of 3,900 horsepower. Union Pacific used a lot of these combinations in freight service after the demise of long-haul passenger service. They were very effective. There was little on-line switching so visibility wasn't an issue. The E unit's switcher sized conservatively rated prime movers were quite reliable and long lived as were the F7 B unit's. There were a lot of miles rolled up with these units long after others would have thought them obsolete. So, even if your railroad doesn't have passenger service, there is a prototype for using "passenger" units in freight service.
ndbprr wrote:...........The F3 engines had a lower amperage traction motor rating then the F7s. So when watching the ammeter when running an F7 if there was an F3 in the consist it could be burning up the traction motors..........
From the far, far reaches of the wild, wild west I am: rtpoteet
On every EMD on which I've turned a wrench -- Dash-2 and older -- there is no current-limiting device. No circuit breaker. It would be a bad idea to have one! There is a ground relay to detect shorts to ground, but that's not the same thing.
The drawback to a circuit breaker is it cannot tell if the overload is intentional or not. By enabling very high currents for very short times, which are within the capability of the D.C. traction motor for at least a minute or two, the locomotive can start a much heavier train that it would otherwise could if it was current-limited by a circuit breaker. Yes, it does require the engineman to pay attention to the short-time rating on the ammeter, but that's not unreasonable.
Different short-time ratings between the different EMD models is for practical purposes inconsequential. The ammeter needle is dancing around in a narrow band on a dial and at very heavy loads the short-term rating is, for example, 2.1 minutes for one locomotive and 2.0 minutes for another. If an enginemen loads his power into that regime all of the motors -- not just the weakest ones -- will be smoking.
For models where short-time differences was consequential, such as between 4-motor and 6-motor locomotives, EMD included power-matching circuitry to ensure that the 4-motor locomotive had similar motor-heating curves as the 6-motor locomotive it might be in consist with. For example, in the Dash-2 line the PF21 module derates the GP40 from 3,000 traction hp at 22 mph to 2,200 traction horsepower at 11 mph, or about the same hp per motor (500-550) as the SD40-2 it might be m.u.'d to.
RWM