From Indian Equator:
I AM ANXIOUS—as ever—to not just follow the same route as Mark Twain but also to use the same form of transport. From Delhi to Lahore then was a simple and quick train journey on the Flying Mail, one of the fastest and most prestigious Raj train routes connecting Karachi, Delhi and Lahore. Not so today. Since Twain’s time we have had the disaster of Partition in 1947 and Lahore now finds itself in Pakistan. Between Delhi and Lahore the India-Pakistan border is one of the tensest in the world, especially now since roguish tendencies in the ISI, the Pakistani intelligence agency, have been shown to have sponsored the 2008 terrorist attacks in Mumbai. It is also one of the most poignant train journeys in the world, the scene of inter-tribal religious massacres just prior to Independence and Partition when half a million people died—and as many as sixty thousand of them making this very train journey, massacred along these very tracks. (page 201)

In Mark Twain’s notes he reported that he left Delhi at midnight and arrived in Lahore at 05.30 a.m. next day, 18 March. I can only presume something is wrong with the note as no train then, not even the Flying Mail on which he would have been traveling, turned in that sort of speed. Nevertheless one thing is certain, it would have been a lot quicker then than the slow chug of a folly that makes the journey today.
As I am sitting, swaying and jolting on the Samjhota Express it is good to read his notes again, if only to remind myself why we are making this trip this way at all: only to follow in his train tracks, as every guide book and tourist forum insists this is the worst possible way to journey from Delhi to Lahore. And the border crossing complications haven’t even started yet. And two sets of unpleasant, deadly memories are right here with us on these tracks.
(p 203)