Make train/wagon settings blueprints usable before robots

[everlate]

TL;DR Placing train blueprint over an existing train should be possible and copy blueprinted settings

The train/wagon settings can be copy-pasted, but the template train must be already built somehow.

There are several cases, where using blueprints with train/wagon settings is almost mandatory:
1. Complex circuit conditions in schedule.
2. Yet non-existent stations in schedule
3. Complex wagon filters for construction/building trains

Now the only way to embody the blueprinted train settings is to build the train with construction robots, but the trains for cases 1-3 appear earlier. For example, when robots are researched, the construction train should be ready and contain items.
Every other entity, when overwritten by the ghost of the same type copies blueprinted settings and this saves a lot of effort in early game. It would be nice and consistent if complex trains follow the common logic.

[ssilk]

Hmm.

This reminds me to the other idea of train routes.

viewtopic.php?f=80&t=53473 Assign Trains to Schedules (Train Routes)
viewtopic.php?f=6&t=34887 Add Train Routes (rework train)

I would prefer that solution, because a) it makes trains more independent from blueprints - think to modding b) it is less complex and allows to change a lot of trains at once, just by changing the route c) a blueprint is fixed in the direction (well, it could be rotated), but especially fixed to the form (cannot paste over a train stating in a curve, when the blueprint is straight).

What I like with this idea, is that it allows to change wagon filters etc. And indeed - when I think about it - technically train routes could be some kind of “special blueprint” that are pasted over trains, when the blueprint changes.