What do you think about allowing an infinite rail grid with such a rail set in configurable intervals?

For the signal placement this could be useful -- to avoid only one automatic train only being able to pass:
Within the crossing, place a signal immediately after each perpendicular rail.
Between two crossings, placed a at configurable interval, but with a different configurable length for the first one. (Players might want to have a different offset / first segment length depending on how much space their intersection blueprints -- e.g. roundabouts -- use, and how long their trains are.)

Placing the map center in the middle of a grid cell and not a crossing at the (0,0) cordinate would probably be preferrable, to keep the starting area usable.

See https://imgur.com/FnzuYpg -- I'd prefer the first grid interval input, and have the mod calculate the second one.:
real_interval := input_interval + (0.5*center_spacing) + (track_spacing * (rails_per_side - 1)) + (2*rails_per_side)

track_spacing is currently also 4 tiles with default mod settings, but I don't know if this is currently hardcoded to 4 or just always equal to the center_spacing value.

So basically you'd like to have intersections automatically generated at regular intervals? Just that or would you be more interested in a city blocks arrangement where a grid is generated in all directions?

The second one -- automatic intersections might be a bit complicated and everyone prefers different ones, and they might be overkill. The idea is to have only a simple crossing, that only allows each grid line to be used as this central line, with the minimal signaling necessary to avoid parallel lines becoming a single block of rail; no chain signals.

This time an ingame viz: https://imgur.com/r4LgcK9

Usage example: Drive north, place a few pieces of diagonal rail and four curves to allow turning, drive east, reach the distant ore field. This would already be sufficient for automatic trains without chain signals.

Center spacing is already adjustable in settings in a limited way. It should actually be increased as the older limit isn't useful anymore.

I'm thinking that I'd do this grid rail approach vertically so that essentially it would be equivalent as if you had rotated 90 degrees.

I'm refactoring the mod at the moment to support NorthSouth as well as the existing EastWest. Support for a grid is possible. I'll probably add grid rails after this work is done.