Is there a way of customising a train formation on scenario planner? If not does anyone have any thoughts on it being made possible in the future?
A consist creator/planner/editor would be a terrific improvement to the game, but it's not on the road map so it's not coming. There are limited train formation options in the scenario planner. Sam did hint some time ago about Scenario Editor "2" which might include some changes in consist choices.
I think what that means is that DTG will be expanding the amount of formations for the trains in said routes (for example: they could create a formation of an F40PH 2-CAT coupled to 3 Nippon Sharyo carriages). What it doesn't mean is that we can create our own formations. Well, that is what I am getting from it.
If you want to make custom formations you need access to yard tracks with manual switches and no signals. The only lines that really work well for this are the Oakville Sub in Hamilton West yard and also the Long Island City yard with the LIRR. The german lines all have signaled switches so you can't pass them, same problem for the British lines. The real shame is they all have yards that could work for this, but you can't use the tracks. What you do is set up a service that you want to operate, then set a bunch of trains up on the other sidings. Make sure the departure time for the other trains is a few hours after the one you drive to give time to switch. Then all you do is switch around to connect the train up ( you may need to break the train up in sections if you want a long one) and away you go. So below I took 4 different formations of GP38-2s and coupled them all up to make an 8 unit light engine move. Also I set up a freight in this spot by uncoupling the lead unit and putting it into a side track, then you use the other engine to pull the opposing train into a siding, run your first locomotive onto the rear of that train and off you go. The last image is on the Oakville sub doing an 8 unit light engine run.
So with North American routes you can't choose a train of all intermodal well cars or all boxcars. This is what they mean by consist improvements in how I'm reading it in that they'll give us more options for which freight cars we can set up our trains with.
So will Will we be able to hook different locos from different routes on one train, put how many locos and cars we want and the direction they face?
They are just going to add more options to the list the game gives you when you try to select a consist for the scenario designer. As far as we know different DLCs are incompatible (I.e. all intermodal consists will be with the BR185.2 for german routes, and not available to the MSB/RSN Br185.2). That's why, as far as I know, the BR182 only has DoSto consists right now. We don't know if those additions will enable you to use locos and cars from different DLCs, given the fact that they tried with the BR182 but failed and had to push that back, the only thing I would expect is being able to use intermodal cars with the AC4400 and the Dash 8, and probabily, as said before, different alternatives of the F40PH and Baby Bullet consists, or even more likely some more options with the UP SD40. Of course there is the possibility it's going to be better than that, but I would rather set my expectations low and be surprised. No consist editor, as far as we know, is in development, if it will come in a distant future