Factorio Forums

to replicate:

place rails in both horizontal / vertical axis, and in some arbitrary 22.5 degree curves or 45 degree curves
place a rail/chain signal on horiztonal / vertical rail
pick up the rail / chain signal to your cursor just as if you were gonna place it in the world
hover over the 22.5 / 45 degree areas to align the rail / chain signal with that curve
after aligning it, hover over the horizontal / vertical rail / chain signals
you will see that they do not align, and you can not see the train visualization length ghost indicator anymore.
in 1.1, you could see that.
it also works in reverse. if you align it with horizontal or vertical axis first, and then try to hover it over already placed 22.5 or 45 degree aligned rail or chain singals, the train visualization length ghost won't show up on train tracks.

I'm seeing this, too, still in 2.0.12.

Video of the visualization issue in action:

https://www.youtube.com/watch?v=fMWMqSCC26Y

For more description of the problem, in case it isn't clicking:

If the player has a rail signal on their cursor and is attempting to see the rail visualizer at an existing rail signal's place in order to figure out a proper next placement spot along the rails, but the cursor signal item is at a different angle from the existing signal on the rail, you will not see the rail visualization appear, because the game says that the cursor's signal cannot be placed overtop the differently-angled one you're hovering over, making it show the "red/invalid" ghost.

You have to re-align the signal item on your cursor with the placed one on the surface before the cursor signal will show blue (already exists here) instead of red (invalid placement) and the visualizer will start to show up along the rails.

Using the R key to rotate the cursor's signal will work, but it is tedious.

Hovering the signal that's on the cursor over an appropriately-angled placement spot on the rails will re-align it, but that can be a little tricky if you have several differently angled rails in the local area.

Suggested fix: Hovering a cursor rail signal over a placed rail signal should rotate the cursor rail signal's angle to match that of the hovered placed one like it already does with chain signals and with the green/white rail signal placement indicators, so that the rail visualizer can always appear.

Note that holding the other kind of signal, it will align to the signals you hover over. Chain aligns to rail and vice versa, they just don't align to themselves.