History question regarding Alco PA's

Discussion in 'The Real Thing- North America' started by Herc Driver, Jan 11, 2007.

  1. 60103

    60103 Pooh Bah

    AFAIK, the FT was the only production unit with permanent coupling (drawbar). Might be some other early units. The early streamliners (F3, E7, PA) were frequently ordered as sets with the same number but a letter added. The original thinking was that they were one loco, but practical railroaders found that any of them could be coupled together.
  2. TrainNut

    TrainNut Ditat Deus

    I don't have an answer to any of your questions but just wanted to compliment you again on that engine. I love it!! I can't wait until my Precision Craft PA/PB set gets here. Deliver date has been pushed back to February 7th.:curse:
  3. kitsune

    kitsune Member

    As a further note, the main reason that the FT was offered as a drawbarred 2 or 4-unit set initially was for marketing purposes. The FT was billed as either a "four unit, 5400 horsepower" or a "two unit, 2700 horsepower" locomotive, making it more on par with common "super steam" engines of the day. Alco also did this with the FA line, marketing the FA1 as a "four unit, 6000 HP" engine.

    Many FTs, like the other Fs and FAs, were later "broken up" into individual A and B units.

    The PA was never offered as a drawbared unit. I do beleive, however, that Santa Fe commonly ran A+B or even A+B+B consists in it's passenger fleet.
  4. Herc Driver

    Herc Driver Active Member

    Thank guys for the great history lesson here...I really appreciate it.

    TrainNut - we're both waiting for those Precision Craft PA2's...I ordered one D&H and can't wait for its arrival. Of course, now I'm trying to find a D&H passenger car to go with it. But, there's plenty of pictures of Amtrak using D&H PA2's when Amtrak took over the route structure...so maybe there's new life for my old Amtrak phase 1 cars yet.
  5. liven_letdie

    liven_letdie Member

    Ah, thanks for the clarification. I could have easily misunderstood at the time that two unit/four unit meant mandatory configuration. It makes sense from a marketing standpoint too. Thanks again! :thumb:
  6. Herc Driver

    Herc Driver Active Member

    Ok...I don't mean to be really stupid here...but let me ask this:

    Was there a common or standard connection that would allow you to hook an Alco unit to another manufacturer? Say EMD for instance? I don't think I've ever seen a picture of a PA hooked to an E or F-unit.
  7. railohio

    railohio Active Member

    The same knuckle coupler that connects engines to cars and so on down the train.

    If you've not seen a PA hooked to an EMD then you're just not looking hard enough. I could pull just about any book off my shelf and find a mixed consist; in a few I could even find a three or four builder consist. Just depends on what the railroad had and what they needed it to do.
  8. Herc Driver

    Herc Driver Active Member

    You're right - I haven't seen enough pictures, and I wasn't very specific in my question either.

    The books I have don't have any shots of an Alco/EMD mixed diesel hookup, so I wondered if there was some mechanical reason that the diesels couldn't be attached like they do today. I guess all the MU hoses were "common" even back then? I understand the couplers were the same (basically) but wasn't sure the electrical/air hoses were all common as well. It seems like almost every model layout picture and every picture I've seen from the late 50's/early 60's always showed a pair of the same type diesel (Two PA's, or two E8's for example) so I wondered if (in real life) this was done for a mechanical reason or possibly a marketing reason.

    Well, I'm going to search on railpictures and rrarchives websites and see what I find.
  9. kitsune

    kitsune Member

    Errr... Brian, great sarcasm, but flawed.

    What he didn't really mention was the ability to consist the engines together through multiple unit cables. MU cables were generally universal, and allowed a ostler to create consistes of almost anything he wanted. So in that term, yes, you could hook an E8 to a PA-1.


    Locomotives from differing manufacturers did not always "play well" together. This was due to two factors: load time and gearing. Regarding load time, EMDs are notoriously slow to respond to throttle changes, while Alcos and GEs have tradtionally been rapid to respond. This response time is what is called "load time". Mixing locomotives with incompatible load times would be similar to trying to hook up a Tyco GP20 to an Athearn Genesis SD70MAC -- one would always be dragging or pushing the other around. Too much of that and a coupler can break or even shear right off it's drawbar, not to mention it's just not fuel efficient.

    On compatibility and gearing, locomotives could be ordered with differing "gear ratios". For example, a locomotive might be ordered with high gearing for passenger service, or with low gearing for drag freights or switching, or a mid-level gearing to be a general road unit.

    In manifest freight service, it was not uncommon to see engines from multiple manufacturers mixed after the early 1950s. On the other hand, passenger trains and high-priority freights (such as TOFC, intermodal, reefer expresses, etc...) would usually have locomotives of matching manufacturer, if not model, in order to ensure optimum performance. Although I've seen vast mixtures of locomotive models in passenger consists -- E7s mated to GP9s for example -- I don't think I've ever seen a mixture of manufacturers, though I'm sure someone obscure did it somewhere.
  10. Herc Driver

    Herc Driver Active Member

    Thanks kitsune...that makes sense...load time and gearing. I have a book on diesel operation, but it doesn't really go over the physics and pure mechanical aspects that deeply. I appreciate the info.
  11. Triplex

    Triplex Active Member

    In the early days, EMD, Alco, FM and Baldwin diesels couldn't MU with each other! At some point (maybe around 1950?) Alco and FM switched to EMD-style MU, so their newer units couldn't work with the older ones. Naturally, sometimes older Alcos and FMs were converted to EMD-style MU. Baldwin continued to produce incompatible engines until the end.

    http://railpictures.net/viewphoto.php?id=145102 PA-1/E6B/E8A consist on SP in 1953. This sort of thing did happen. The reason engines often ran like-with-like was (at least partly) that many railroads treated a locomotive as being a set of engines. Even though they weren't ususally drawbar-coupled, an F7 A-B-B-A set, for example, might be treated as one locomotive, given numbers like 100A-100B-100C-100D, and maybe even not uncoupled except for maintenance. At the very beginning of diesels, this was caused by union regulations requiring one crew per locomotive. Thus, to be able to use diesels' MU capacity, they needed to count several locomotives as one.
  12. kitsune

    kitsune Member

    To expand on Triplex's mention of union rules, many early roadswitchers were ordered without the capability to MU, as the union agreements of that particular road forbade it. In steam days, MU'ing was almost unheard of -- a double header required two crews. Although technology allowed diesels the ability to MU together, unions objected to this. On some roads this situation lasted for some time.

    One example I am familiar with is the SP&S, who had to order their RS1s without MU capabilities. Later models, however, such as the RS3, came equipped with MU capabilities as an agreement had been negotiated with their union by that time.

    In some cases, even after an agreement had been reached, a locomotive without MU might remain that way until the end of it's service life. I can think of a few engines -- primarily early EMD switchers on small independent shortlines -- which still have no MU capabilities.
  13. railohio

    railohio Active Member

    Another example of non-MU is on the Susquehanna in New York state. Their units were numbered ending with an odd number if they were not MU-equipped and with an even number if they were. This practice was carried over into the 1990s when they ordered new SD70Ms; the units carried the numbers 4050, 4052, and 4054. Most railfans believed they had five units because of the range of the numbers when in face they only rostered three.
  14. Triplex

    Triplex Active Member

    Then I guess I'm not most railfans. Don't assume that engine numbering is always sequential and without gaps. Some railroads gave cab units even numbers if they were As and odd numbers if they were Bs. When Santa Fe (re)built its CF7s, they were numbered in reverse order of production!
  15. brakie

    brakie Active Member

    And roads like PRR didn't really follow a set number pattern.
  16. Russ Bellinis

    Russ Bellinis Active Member

    Another thing that restricted the ability to mu locomotives was simply because the design of the locomotive bidies created logistical problems for crews. If a locomotive broke down enroute, it might be necessary for a crew man to go make a phisical inspection of the broken down unit. In the case of Fairbanks Morse, the walkways were significantly higher than EMD units. On the Santa Fe, at least they didn't mu EMD units with F-M units because of the difficulty of a crewman trying to move from one unit to the other safely while underway.
  17. Triplex

    Triplex Active Member

  18. Herc Driver

    Herc Driver Active Member

    Guys...this is great info! Thanks!!!

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