In my era of interest, the 1930’s and early 40’s, the standard railroad coupler in North America was the Type E. It was found on both freight and passenger cars. Here are two pictures from the 1941 Locomotive Cyclopedia:
When lightweight high-speed passenger equipment was introduced a new coupler was too, effective March 1, 1940. The Tight Lock Coupler (later called Type F) was designed to eliminate free slack in the contour (vertical plane). It has a tapered protrusion on one side that engages in a tapered pocket on the mating coupler. It can couple to a Type E and has the same strength. Here are some pictures from the same volume:
My preference is to use Sergent couplers for my models and naturally their Type E predominates at Fillmore. Fortunately they do offer a Type F Tight Lock coupler in standard shank length. I ordered a couple (sorry!) as these would only be found on a select few passenger locomotives that led the new lightweight trains.
One such locomotive is NYC 5426, a streamlined Class J3a Super Hudson, one of two that pulled the 1941 editions of the Empire State Express. But, this was not a simple coupler swap as it should have been. The MTH model had the coupler and box mounted too far back, no doubt to accomodate very tight model railway curves when coupled to a typical model railroad passenger train set. Here is a picture:
I did not like the look of this. However, I did not want to drill and tap a new hole a little farther back as the wall section is quite thin and did not want to break through to a visible model area (above the buffer). Instead I opted to make a custom coupler box with a mounting screw far to the rear where it was safe to drill & tap through the tender chassis. Here are pictures of the part I designed in 3D.
While doing this in 3D, I naturally thought that I should get this part made at Shapeways. I also added a mounting pad for the two air hoses found on the right side as well as a cover plate (made as one piece). The cover plate is removed from the printed part and assembled to hold the coupler inside.
In retrospect, I should have scratchbuilt this the old-fashioned way, not that there is anything wrong with the Shapeways printed part. It’s just that I could have made it faster and much less costly the traditional way. Live and learn….advantages of the printed part are that it is one-piece for strength and more accurate than I could have done by hand.
Here are some pictures showing the printed part mounted.
I had to assemble and paint the Sergent coupler (this is covered in a post found in CATEGORY: XTRA – EMC 103/103A “COUPLERS PT2”).
I think this is a big improvement! Now what about 5426??????