You have to take the pilot off totally to really swap the coupler, it's a bit of a PITA.   Why they used a straight slot screw there also totally befuddles me!

Like John says, you have to remove the pilot to do it.  It took me a while to try like you did, then start looking for the needed screws to remove to get the pilot off.  Once I did it and got it back together, double heading was fun.  But due to the work involved I'm leaving it on the front.  I wish the manual had instructions on how to swap it, or better yet lined up a hole with the screw so that you can swap the coupler without taking the front apart.

On the other hand, it's a nice simple coupler and I wish I had a handful to use to add to the front of my non-scale steamers from K-Line and MTH after cutting off the fake molded couplers on the front.

Sinclair you can get the couplers from MTH parts. I got mine at York meet.

Clem

MTH sells Lionel dummy couplers?

J/K.  Anywho, I know you can get couplers from MTH, but I've never seen a MTH one so I don't know how similar it is to the Lionel one that I know would for for me.

As much fun as it may be to couple two Big Boys together, they were never run like that.

The whole reason for the Big Boys existence was to do away with the need to double head engines.  Double heading required stopping the train to add/couple helper engines, and slowed down freight operating schedules.

And THAT is why I never doublehead my Big Boys.

I just don't see any reason to do it.

My Imperial Railking Big Boy can pull more cars than I can get on the layout, so why add more power?

they run like that in my world

Then I guess you would freak out if you saw me double head a BB and PRR T-1?

Besides, you argument is invalid because there is a prototype for everything.

A Challenger and Big Boy Double Headed....

I have a Pentrex video that shows 2 Big Boys double headed.  It was not a common practice but the UP did do it.  I think I have a pic of double headed saved somewhere.

Yes the 4000's were dbl headed but it generally was a power transfer.

Here's a thread where we discussed the coupler swap with some Pics.

VL BB O Gauge Coupler install question

Yes, the phrase "...they were never..." is always a dangerous one in this arena, and

most others.