Doesn't matter much what it is. If the settings on the wagons are not good, like lots of older freight wagons are, then the problem persists, no matter if you transport fresh air or some families of (un)happy hippos.
Empty car transporters catch quite a lot of wind in real life. So this might be more realistic than you think. The drag causes the train to 'feel' heavier than, for example, a container train which weights twice as much but has better aerodynamics.
That's an interesting thought, actually. Anyhow it provides a good reason to keep the power on and enjoy the lovely sounds of the loco! (Much nicer than that buzzing CD 163 in SimRail!).
Update... Yes it must have been the wagons as I've just started a fresh run on RSN and it is accelerating slightly with power off on the down gradient leaving Hagen. Superb loco!
To add to what others have said already, don't forget that empty trains generally coast much worse than the same trains, but loaded. That's because you have the same drag from air and rolling resistance, but much less mass to counter it with. It's not uncommon for long empty trains to slow down even on slightly descending gradients.
Xbox series x. Ran out of memory heading into Stuttgart about a mile away. It's the first run in the first chapter of the journey. Decided to give it a chance because it was on sale, and on my first playthrough it crashed to dashboard. The route is actually very detailed and was leaving some good impressions on me but not anymore. Please look into this
Set your graphics settings on HD... try to just drive the train.. reduce the amount of sightseeing and photo mode. You dont want to stress the UE4 engine if it is not needed. Quick resume can also cause you to run into troubles... Do not use Quick resume if you do not need it. I just did your journey run on Series X with all the layers on... I continued in freeroam after i finished the journey and did some sightseeing on stuttgart hbf... and did 3 sbahn services without crashing. But yeah.. those blurry textures It is what it is on Xbox i guess... fingers crossed if DTG can fix this. Stuttgart Heilbronn is a great route with all layers enabled.
Just finished SE 19823 from Heilbronn to Stuttgart. When departing Bietigheim-Bissingen, the main signal showed Sh1 instead of Hp1, which it shouldnt since I'm not shunting or going to any siding, but departing for Ludwigsburg instead. I was able to pass the signal with "Befehl 40", as usual with a Sh1 signal. Right after that, the very next signal (no. 266) has a hot 500Hz magnet despite showing Hp1 both on the map and otherwise. Wasn't expecting that and got zwangsbremsed. Just about 5 meters behind said signal, there stood a sign notifying me of an upcoming temporary speed restriction. But the sign was weird, it had no number indicating the upcoming speed limit on it. This one might be mod related though, I'll check it out. No further issues (thankfully), arrived at Stuttgart with 4 minutes of delay. Afterwards I did the followup service, heading to the cab car and bringing the consist to the yard. Despite being relatively empty this time (only 5-6 passengers travelled to the yard with me this time, is that progress?), the background chatter in the cab made it sound like there's a party going on somewhere behind me.
