Most railroads were limited to 79 MPH, above that you had to have in-cab signalling or some other safety devices that most railroads didn’t want to pay for. But ATSF usually did have very well maintained track, I know they didn’t have trouble with their RSD-4/5 models the way some other railroads did…apparently because of their superior trackage.
BTW I rode behind a GN E-unit on the Badger (Twin Cities - Superior WI) in 1969.
in the late 40s and early 50s SOU had ATS installed in the passenger E’s and F’s and some freight F’s but rapidly removed the systems. Used same trackside equipment that is still on the LAX - SAN surf line.
The extra 4’ truck centers of the FP7 is an altogether different (meaning better) ride than a regular F unit. The Rock Island had three high speed FP’s and I’ve ridden them at the century mark on stick and welded rail, no hunting.
However, a regular F unit with the 30’ truck centers plus 9’ truck wheelbase equates to two wheels on each side on a rail joint at the same time when riding on 39’ stick rail. If the railroad is “Low joints and high centers” you will feel it. The FP7 will glide right over that same track.
Another plus for the F/FP is that a 102 mph gearing has a minimum continuous speed of aprox (my books are still packed away) 13.5 mph and the E unit’s min cont. speed is aprox 25 mph. That kind of tells the tale why the ATSF, GN, NP, CP, CN nd SOO used F units (+geeps) on most or all of their long haul trains.
As a point of Clarification, EMD built the FP45s for passenger service on the Santa Fe in 1967 BEFORE they built the SDFP40s for Amtrack in 1973.
The last E9 rolled off the line in 1963 and the last F unit in 1960.
So there was only a very short period where they didn’t have purpose built passenger units and that ignores the hood unit passenger units like the SDP40 which was built in between.
“Hunting” was horrible on F units, especially on jointed rail. The C&NW had old 39’ stick rail from Waukegan to Kenosha, and the suburban trains ran at 70mph. We would swear sometimes that we were going to topple the rails due to the trucks banging the rails so severely. Most engineers would keep the speed down to 60 or so due to the condition. Riding in the E units was like riding on soft cushions (at least compared to F units).
? Was the rough ride due to the 39’ stick rail in relationship to the center to center measure on the trucks themselves, or the center to center measure on the axles on each truck?
Murphy Siding wrote the following post at 06-12-2008 8:56 PM:
? Was the rough ride due to the 39’ stick rail in relationship to the center to center measure on the trucks themselves, or the center to center measure on the axles on each truck?
Truck center to truck center is 30’. Each truck has a 9’ wheelbase. These measurements equate to the front and rear wheel on the right side being on a rail joint at the same moment which then shifts to the left side as the front and rear wheel pass over the joint at each end of the 39’ rail. Plus the rear wheel of the front truck and front wheel of rear truck also pass over the rail joint, but not at the same time as they are only 21’ apart. At 60 mph this all happens about twice per second. So if there are low or battered joints you can imagine the near twisting motion that’s going on under the locomotive. Eventually all this wear seems to tend to elongate truck center casting, which adds lateral motion to the mix. As you are going down the railroad hanging on to the seat and brake valve for dear life and listening the the beating the side bearings are taking, you tend to wonder how it all holds together.
The 30’ truck center was one of EMD’s “Goofs” IMHO, but when it was designed the stick rail was maintained to much higher standards.
Did the GP7/9/etc… have the same wheelbases, and the same issues?
GP7/9/18 has 31’ truck centers and ride better than the 30’ F unit on rough jointed rail. Don’t know what the BL-2 truck centers were.
EMD inadvertently gave the GP7/9/18 a built in branch line speedometer with the 31’ centers. When the unit started into a hippity-hop motion, it was telling you “Fast enough”. Confirming the speed with a watch check usually showed you were going just a couple of miles over the posted limit.
I have never experienced a bad ride in an F7 and F9 that was any worse than a GP40, SD45 or SD40 on the same track, and I have lots of mileage on 39’ stick rail. I always thought the Fs rode quite nicely, especially compared to a GP40, which can be pretty bouncy, the worst being the wide-nose CN locomotives because they’re nose heavy. The difference may be in the truck maintenance standards at different railroads. The outside swing-hanger truck has lots and lots of wear points. Most of my mileage back when F units were still running was on western roads that had a lot of money and kept after their power – so much so that when we saw anything but clear exhaust from a GP or F at full load we wondered what was wrong with it. I have always appreciated the way an SD45 or SD40 will just float through a rough spot while the next day on an AC4400 at the same place it feels like it’s derailed already.
RWM
Railway Man:
The point I was trying to make was the difference in ride between the F7 and the FP7 and not so much as how bad the F7 rode.
My personal opinion of the F7 is very positive, but as was mentioned on jointed rail with lots of low/battered joints the ride could get “Interesting”. I fully concur with what you say about the GP40.
boomer – I had some time in FP7s but never noticed a difference in ride. I don’t doubt what you say one, however.
RWM
Would the CF7’s have inherited the same problems?
Maybe, but it probably wouldn’t be relevant, since CF7’s were designed for switching / road switcher service, not high speed passenger trains. F units don’t offer very good visibility to the rear so don’t work so well as road switchers, so Santa Fe converted them to having a more road-switcheresque body.
Back to the original question, remember too that the period of time when F units were the preferred diesel engine for freights was fairly limited, basically 1940’s to the early 1950’s. Even though F9’s made it to 1960, many railroads had started to shift their attention toward road switchers like the GP-7 and RS-11 etc. already. In fact, that’s part of the reason the Soo Line bought ‘passenger’ GP’s in the fifties with the torpedo tubes on the roof - GP’s could more easily be used as freight engines once the railroad ceased passenger operations.