One of the goals in this build of EMC 103/103A is to successfully operate Sergent Couplers, where diaphragms interfere with using the usual coupling/uncoupling tool.  Sergent offers a special tool (more to follow below) for aligning/opening-jaws/uncoupling for diaphragm-equipped passenger cars.

When I built my original 2700 hp Demonstrator and NYC 1600/2400 I was not concerned about the back-to-back coupling of the second sections to make an A-B-B-A configuration, as these were intended to be A-B sets.  At that time my standard coupler was the Kadee #158 “scale” coupler with the trip pin/glad hand snipped off.  I had no trouble coupling onto a freight train with these.  However, in using the standard length Sergent Type E coupler, I find that they are obviously too short (as seen in the photo below).


The second section in the above picture is from my original 2700 hp EMC 103.  Since it was only an A-B configuration, I had cemented the American Limited diaphragm in the squeezed position (all the way in).  At the time I had no need for working diaphragms and if I left them “operational”, they had a bit of a droopy look.  Using this model helped me evaluate what to do to solve the short couple situation.  The coupler is about .075” short of the end of the diaphragm.  Modifying the coupler mounting is not possible.  I think I can use the Sergent extended Type E couplers that they offer.  They are available in .100” and .130” longer lengths.  I sent an e-mail to Sergent describing the problem and asking for their opinion about my thoughts on using their extended couplers.  They did not reply.  So, it is up to me to make things work on my own.  I have ordered sets of both lengths.  My thinking is that the .100” might be enough as the extra .025” hopefully will make up for slack and provide clearance for the diaphragms to work around curves.  If not, then the .130” extended ones may do the job, or a .100″+.130″ combination.

Checking the 103/103A chassis, the coupler height was bang-on using a standard length Sergent Type E coupler as seen in the picture below (and using the Sergent coupler height gauge).


The standard Sergent Type E coupler fits at the front position as well, below.


Here are two pictures of the special passenger car uncoupling tool.  The magnet is the horizontal rod inside the resin block just below the long handle.  This magnetizes the flat bar with the ring at one end and a tab at the other.  Sergeant couplers have a tiny steel ball inside that locks the jaw shut.  This is done by gravity.  When the ball is raised with a magnet, the jaws unlock and uncoupling happens.  The brass wire is used to open the coupler jaw.



The problems I had with Sergent Type E couplers when testing with Walthers Heavyweights were (and I did use the special passenger car uncoupling tool):

  1. Aligning the jaw because I could simply not see it (the Sergent coupler uses a small Kadee-like coil spring, but only for friction to prevent the coupler from flopping side-to-side.  These couplers are not self-centring; the operator needs to centre the coupler, just like on the prototype).
  2. Also just like the prototype, the operator needs to sometimes open the jaw.  I could not get the tool in between the coupler and diaphragm to do so.  By the way, if a car has been previously uncoupled at a car spot, and not disturbed, often the coupler is already aligned and the jaw open, ready to be coupled again.
  3. Uncoupling the car: getting the tool above the coupler under the Walthers diaphragm was just about impossible.
  4. In addition, to uncouple any coupler, like on the prototype as well, slack between the closed jaws is necessary.  The springiness of the Walther diaphragms was too strong and I could not get enough slack without moving the car I was backing into.

Admittedly, having other fish to fry at the time, I did not pursue solutions to the above problems.

I would like to add that my layout height, at only 42-1/2”, is very convenient for working with Sergent couplers (for both freight and passenger).  I find this relatively low height allows one to come in from the top of the model to align couplers/open-jaws/uncouple more easily than doing so on a layout that is at a higher “railfan” level.

Although I did not have the extended couplers, I was able to experiment with a standard Sergent Type E coupler mounted in the second section of my now defunct EMC 103.  The following pictures show how Sergent couplers are operated with the passenger car uncoupling tool.

In the picture below the coupler is over to one side and the jaw is closed (American Limited FT diaphragm is above it)…


…the ring-end of the tool is used to nudge the coupler to the centre position…


…the ring is positioned over the coupler to raise the internal steel ball…


…allowing the brass wire to open the jaw.


To uncouple, after putting in some slack, the tab end of the tool is placed between the coupler and diaphragm.


It is obvious that my earlier troubles with uncoupling Walthers heavyweight cars lay in their design of the diaphragm (not enough clearance for the Sergent tool).  Perhaps by re-equipping these cars with American Limited diaphragms I will have success.  Another project for the future.

I wish you peace and happiness.

FT Tidbit: There was a very rare shortened second section (B-unit) that was available, possibly called the FTSB.  Shortened by six feet, it did not have the rear overhang like a typical second section, nor could it have a boiler (for passenger car heating).  This car body would be found on factory A-B-A sets, although not all A-B-A sets had them.   I have seen pictures of the Chicago, Rock Island & Pacific (CRI&P), the  Delaware, Lackawanna & Western (DL&W), and the Minneapolis & St Louis (M&StL) with these sections in A-B-A sets.