150m can do a whole bunch when you use properly rolled out busses, with their own lanes (and you can initially paint these if the budget is low). People driving their car on the bus lanes will nicely generate additional tax income (fines) and if the busses are good, the people will come.

Even in the Netherlands, where we have really good trains on even a European scale, we still have long-distance busses (comfy ones, for 1-2hr trips) and regional busses (still comfy, but those are 20-30 min trips). Custom infra doesn't always cut it, especially when repurposing existing infra will serve the job just fine.