Hi James, if you get the time to do this (because Ik your busy), can the class 399's be modded to be able to run off AC overhead current as well as DC overhead current please?
That is actually very straightforward, so I have just fixed this now. Thank you for the report.
No problem, I found out about this via Wikipedia (although not reliable)
In current way_constraint system of Britain-ex, we cannot simulate DC/AC vehicles using
way_constraint_permissive[1]=1 #(DC catenary)
way_constraint_permissive[2]=2 #(AC catenary)
descriptions. It requires DC AND AC catenary.
One of the solutions is to separate AC/DC/voltage settings from way_constraint_permissive to way_constraint_prohibitive.
Example for wayobj catenaries:
way_constraint_permissive[1]=1 #(catenary)
way_constraint_prohibitive[2]=2 #(DC electrification)
or
way_constraint_permissive[1]=1 #(catenary)
way_constraint_prohibitive[3]=3 #(AC electrification)
Example for AC/DC vehicles:
way_constraint_permissive[1]=1 #(catenary)
way_constraint_prohibitive[2]=2 #(DC electrification)
way_constraint_prohibitive[3]=3 #(AC electrification)
The problem with using the prohibitive constraints is that steam/diesel vehicles would not be able to travel under the wires, not using the electricity, as was and is common in reality.
The solution is not so difficult: just write "way_constraint_prohibitive" descriptions on diesel car .dat file.
Imho you would have to write all such constraints on all rail vehicles. Including cars, not only engines. That would make problems when adding new catenary type or using older addons without sources.
I have plans to use prohibitive constraints for cog wheel railway, but there also the constraint would be more appropriate only for engine.
A real solution would be to have an option for vehicle, whether all or any of its permissive constraints are necessary. And perhaps an option that such vehicle can enter track without appropriate constrain but with zero power.
And another option for way constraints telling that this constraint is only for powered vehicles.
Actually I have already done such modifications for all train cars since I received just a same request in my server game.
However it is useful introducing zero-powered cars options, I think.
Adding a prohibitive constraint to all diesel, steam and unpowered rail vehicles for various types of electric traction would be a confusing fudge (that they have this constraint would be visible in the UI, and there would be no good reason why 1830s steam engines would have these constraints listed) and logistically impractical to implement.