Take the post stations for the conversations of the markets.
The connection by track is new, I like that. The rules for the inserters needs to be set automatically. It's really not useful, to make the work twice.
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Just for those, who read that and don't know what I mean: currently I've to set up one requester chest for one needed item in the other network. This is because I can't tell an inserter to insert this and that, if not enough. I can tell him only to insert, but cannot control what and how many of that.
The result is, that I need 20 requester chests and twenty inserters, which fill into a train with 4 wagons. To transport 5 belts, or one roboport, or 67 piercing bullets.
(I write from iPad, so I can't do it yet), but when I read your answer I knew, that I've mixed the number up with something else. But well, it was about 100 green wires, cause the way is not completely straight, there are not always big poles.
. It would best be labeled an electric engine and not worry about what fuel source is provided. To provide accuracy, the locomotive could have its name changed depending on fuel source ,coal-electric, oil-electric or wood-electric 
but I think hybrid electric would suffice (although some batteries should be added to the recipe).
