You can't. It's completely random as to which services and scenarios it will be selected for. You can always keep reloading the scenario/service until it loads for you.
You cannot. It is randomly assigned to a train in the session. Sometimes it can be you or you may see it an AI train.
So, good luck! I started about 30 random Timetable Services in both directions, but I still never seen one.
It's assigned to 395012 just like in real life. This train then randomly gets assigned services during the game play session.
I spawned at Ebbsfleet on foot for my second attempt at the route and the Trainbow was in the station. I let it go though because I wanted a 375.
I suggest the following fix. Custom paint some in livery designer to increase your odds. I made a few class 66 schemes and saw them all over the place. If you custom paint one you can select it or at least make more show up.
As I found out!. I had driven a St Pancras - Dover Priory service to see what would happen as they said those platforms were not used at Ebbsfleet (I could drive it but go an out of area message as I got to the platform). I spawned at Ebbsfleet to continue the journey but no 375s so I bailed and went to Faversham instead.
I noticed if you have personal liveries they can take over the look of 395012 making the seeing of trainbow impossible to see unless you restart and hope it doesn’t do it again
Is that true though? I know somebody came up with that number and it has been repeated a few times but I’ve not seen an explanation of how 4% was calculated. Is it known that there are exactly 25 6-car sets in the simulation?
There are 29 sets in real life, so the game probably randomly allocates each train a number from 1 to 29. This would mean the chance of getting it yourself is 1 in 29, but of course the chance of seeing it is much higher. One thing I'd like to know is does the game ensure that no two trains are allocated the same number, as I've seen two with the same number on the scenario planner on the Isle of Wight, but that would mean you could see this livery twice in one run.
They were only quoting what someone else had said though. They never worked it out or said why it would be 4%. It all depends on how whoever came up with 4% worked it out, or more likely had a good guess. If there are the full 29 real life sets featured (so your train’s number can be any of the 29) then it is a 3.4% chance that you will be in the cab of the trainbow for your service. That doubles to a 6.9% chance of having the trainbow as one of the two sets in your 12 car train. If there are only 25 trains depicted (which I doubt) then 4% is correct, or 8% for it being one set in a 12 car train. I’ve rounded to two significant figures for the percentages in case you are wondering how 3.4 can double to 6.9 !!!