Re: Another X29 Question -- Coupler Operating Release Levers

Bruce Smith



My general impression of the transition in the coupler mechanism of the X29 was that the Carmer uncoupling device was considered to be less safe that the bottom-operated rod style. While not be “banned” in interchange, around 1930, with the technological innovation of the “rotary” style uncoupling device, there was a movement away from the Carmer. It has to do with the mechanics of operation. With the Carmer, you have to push down, whereas the rotary rod style, you pull up. You chance of slipping and falling are greater with the former as it puts you more off balance.


As I note, the Carmer levers were not banned, and so they continued in place on the cars so equipped, although as you note, they were gradually replaced, probably, again as you note, when repairs were required. There was never a general effort on the PRR to replace Carmer levers on cars that had them.



Bruce Smith

Auburn, AL


From: <> on behalf of "Schleigh Mike via" <mike_schleigh@...>
Reply-To: "" <>
Date: Thursday, May 13, 2021 at 10:25 AM
To: "" <>, "" <>
Subject: [EXT] Re: [RealSTMFC] Another X29 Question -- Coupler Operating Release Levers


CAUTION: Email Originated Outside of Auburn.

I am getting confused here, Tim----


I do not follow the relevancy of your reference to a 1925 SP tank car.


All my questions were intended to address the Pennsy's use of the Carmer on their X29 boxcars.  Before their end of production the RR switched to bottom operated couplers which ruled out employing Carmer operating levers.  Why did they switch to bottom operated couplers?  Why were some older cars, built with top operated couplers, converted to bottom operated?  Was there an issue with the Carmers?  Or was there an issue with top operated couplers?  Or both?  That there seems to be no evidence that the PRR simply replaced the Carmer with a rotary mechanism suggests that it was the bottom operated coupler that had risen to a more preferred status.  Couplers still need to be replaced; perhaps the Pennsy standardized, as much as possible, on the bottom operated.  This alone mandated the rotary mechanism.


At the same time, anyone familiar with manufacturing would recognize that the Carmer must have been more expensive to produce because of material and labor considerations.  So----no more new Carmers on new cars.


Operating the Carmer was distinctly different to operate than a rotary.  I do not perceive any mechanical advantage to either.  In each the force the hand applies to the lever seems to be about the same as if a hand pulls the pin directly.  However, the hand pushing down operating the Carmer performs very differently than that applied to the rotary pulling upwardly.


But, the Carmer offers some creativity to this process in that the operator can stand higher on the car and push the Carmer using the foot.  This begs the question of safety.  Was safety an issue?


The rotary operating lever offers consistency whether pulling a pin on a top or bottom operated coupler.  Did consistent operation of the uncoupling process suggest the Carmer should be discontinued or perhaps even be replaced?


And what about the bottom operated coupler?  Did this offer some advantage over the top operated?


I did not mean to get too far into the weeds on these questions.  It seems to me that if The Standard Railroad of the World made this production change within their huge fleet of X29 boxcars, they had a good reason.  Is this reason known?


Where I can, I will use dated photo evidence to at least suggest whether my X29 models have Carmer top operated couplers or bottom operated rotaries.  Unless some other evidence arises, top operated rotaries will not be found on those models.


What the Pennsy thought and liked may well have influenced the greater industry and, if that produced at least a general preference for rotary uncoupling levers suggesting discontinuance of the Carmer (if not replacement), that would be an interesting point to understand.


Thanks for your interest in these questions.


Regards from Mike Schleigh of Grove City in western Penna.




On Thursday, May 13, 2021, 08:53:26 AM EDT, Tim O'Connor <timboconnor@...> wrote:




Was it just a matter of a rapid change from top-operated to the bottom-operated couplers
for NEW freight cars, and then the gradual retirement (or rebuilding) of older cars? I have a scan
of a 1977 photo of an SP O-50-10 tank car (built 1925) with its original Carmer lever, and top
operated coupler.

Was there any mechanical advantage (i.e. leverage) that favored bottom operated uncoupling?
Or maybe it was just a cost advantage? (This seems more likely to me, given this is the railroad
business, after all.)

Tim O'Connor

On 5/12/2021 11:42 AM, Schleigh Mike via wrote:

Hello Group!


Contemplating the details of the historic Pennsy X29 boxcars it is not easy to overlook the initial application thereon of the Carmer operating lever.  This was surely a popular option for the PRR on many of their cars but by the early 1930s, with the last of the X29 production, the RR switched to bottom operated coupler release and the very different rotary operating lever so associated.  Thereafter, many but not all X29 cars were converted to the same style of bottom operating couplers and levers.


Is there an established reason for this conversion?


It is easy to speculate that the more modern 'rotary' style of lever is of less cost and material and that there could be safety and ergonomic reasons to move away from continuing use of Carmers for both new and retrofit applications.  So, was there a policy or 'program' promoting this?  Photo evidence of X29s in the late 1950s show some Carmers still in place and I believe I saw them well into the 1960s.  (I don't recall the details.)  No photos have been found of PRR X29 Carmer conversions to top operated couplers seemingly keeping the old coupler so perhaps the coupler change-out was the real driver in those cases of Carmer removal.


It could also be speculated that the operation of the Carmer was so different from the rotary that Labor and/or Regulators at least recommended replacement on rebuilt or refurbished cars.  This also begs the question of top versus bottom operated couplers on freight cars.  Was there an industry move away from the top somewhere back there in the post-Carmer time frame?  Obviously top operated couplers continued to be applied for many applications but did they fall from freight car favor at some past time?


Writing from Grove City in western Penna.....Mike Schleigh


Tim O'Connor
Sterling, Massachusetts

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