Add track segment length as tooltip

When designing train track I often need to check the length of a track segment (track between two designation transitions). For example to ensure minimal distance between switches, check if trains have sufficient space to stick out of stations or to ensure waiting bays can hold a train.
Right now I can sorta do this by planning adjacent track of the size I want, but this hardly works for non-orthogonal track or curved track.
I'd suggest a tooltip added to the track designation tools that shows the length of track currently highlighted. When holding shift these tools already highlight exactly what I want to measure. The info can be either right by the cursor, in the box that shows construction materials or overlayed on the track (like the mining tower's new box). I'd love to see this show in more relevant places like the track construction tool too.
Besides the quick suggestion, my ideal implementation of this would overlay the length of track segments while the track construction tool is out. By default only showing segments that get created or altered by the currently considered track. A hotkey could then show this overlay on every visible track segment.