Summer of 1836, narrow gauge becomes available. Unfortunately, its rather expensive:
Narrow gauge track £150/tile (£14 maintenance) 100 km/h 55t
Standard gauge Plateway £25 (£2) 45km/h 5t
Standard gauge Wrought Iron track £35 (£3) 60 kn/h 27t
I imagine this is simply because there is as yet only one type of narrowgauge track, which is priced to be competitve 50+ years later. I just thought I'd point out the issue.
There's also no steam traction at that time, only horse traction.