Well I just found something similar, though I can’t reproduce it. I was upgrading streets in a town, and suddenly instead of costing $5k a section gave me $2.2B income from construction.  Here’s a screenshot

I should point out I didn’t spend all my money, and had about $115M in the bank when this happened.

In my game plays there were a few things regarding the track building features that I thought it really needs.

– Double tracks building

– Track length counter when building

– Angle counter for tracks in degrees

– Upgrade an entire track route or the whole network to catenary or high speed

– Upgrade all signals on an entire track route or the whole network

– Hybrid train station that can do both passengers and cargo at the same time

– Train stations with more than five platforms

– Add option to replace a train when sent to depot to be sold if a train exists in the depot

– When a track has been placed but not built allow us to add two sections in the middle where we can select the elevation to create a bridge or a tunnel

If you have more suggestion add them here.