Not knowing much how the physics work one often gets fooled into assembling convoys which turn out not to work. Recently I created some horse powered trains just to find out I did not put enough horses on them as they only achieve 1 km/h going up shallow inclines despite being capable of 18 km/h on the flat. Seeing how the line has many such inclines along it this clearly will not work so I needed to replace them.
As such I am requesting a quality of life feature such that ontop of the maximum speed achieved on flat terrain it also shows the maximum speeds capable when climbing an incline, or at simplest a warning that the convoy will have problems doing so. Obviously convoys not capable of climbing steep inclines would not show a value for them. This way one can see during convoy assembly that the vehicle is under powered and more engines/horses are needed if it is to achieve a decent average speed. It would apply to both the depot window and the replacement window.
I can see that this might be useful - although I suspect that it would also be a fair bit of work, not least as I do not know much about the physics engine myself, it (including the current haulage estimates) having been written by Bernd Gabriel some years ago.