I also programmed my TMCC Pennsy Sharks where both engines are powered using the same ID the rear engine always starts in reverse and its coupler always works as the rear coupler.
I have these in a lash-up. I will try them as a single engine. Thanks for the advice as it will save a train number.
I reprogrammed my TMCC PRR Sharks with a single engine number and the engines work well together. My only complaint is the whistle/bell in the trailing A-unit still work, instead of being silenced as in a lash-up. Anyway, it did free up another TMCC Train Number so I'm happy.
All my other TMCC lash-ups have what would have been the lead engine of a powered A/dummy A set* in both the lead and trailing positions. I need to use a Train Number for those.
*I bought two Lionel powered A/dummy A sets, put the powered As together as my running AA consist and store the 2 dummy As. Back then it was the only way to get two powered A units, both with sound.