After making up my mind to buy and download TRS2019 I firstly decided to use a different Google Account with a new email address. I then registered and opened a new account with Trainz using a new Username and password. My proper name, address, account details etc, remain the same. My reason, rightly or wrongly, was that I thought it would cause less friction or confusion, for myself more than for anyone else, if I had the new release totally separate from previous releases.
I ordered the game, had it confirmed, and received the email containing the downloading instruction within five minutes.
I don’t know if by doing the above I have made it impossible for myself to transfer anything I did previously on TANE to TRS2019, I haven’t tried it yet.