Another Portal Problem Thread

I am running TRS 19, Build 114800. I am attempting to bring trains on from both the north and the south on my route. I can get a short ( 1 loco and 4 cars) freight train to emit and follow schedule created. I can get a longer passenger train to work. However, when I try to get a longer freight train, the consist derails behind the locomotive. Now, there is 3000' of straight track from the portal entrance before any signal or junction. I get the same issue on both north and south portal. It occurs with different consists longer than really short ones. This happens regardless of what portal I use: portal, portal basic, portal basic short...(you get the picture)

Before I get roasted for creating a new thread...Honest, I tried searching for an answer before starting a new thread, but what's out there are rather old posts so I don't know if there's any new thoughts out there. If I missed the thread, a gentle push in the right direction will be great. I really would rather not have to create a staging yard to bring trains onto the route.

Same locomotive for both passenger and freight?
If not, use the passenger locomotive for freight to see if that works.

I've also found, just deleting the portal and adjoining track, saving, restart Trains and rebuild the portal from scratch has cleared such issues before now. Peter