Narrow gauges were not universal , they were mostly used on the smaller lines in the mountainous areasHow is Indian railways organized "exactly as it was left" ?
On the technological front, the railways does not use either the steam engine or the narrow gauge.
On the managerial front it is no longer run as a private for profit entity
The fact remains that the British put in all the infrastructure such as the lines , bridges , stations , maintenance depots , turntables , signaling and the telegraph , 99% of which is still in use today .
As regards steam engines , one of the first thing IR did after independence was to paint silly colours and symbols on them .
They were only retired in the last couple of decades , a lasting testament to the quality of British engineering .