First Overland
I've posted a bit before about the "First Overland" trip in two Land Rovers from London to Singapore. Here's a post from earlier in this thread:
https://expeditionportal.com/forum/threads/land-rover-ideas-for-jeeps.218029/page-21#post-2847138
A few videos about the First Overland expedition:
There's an excellent book about the journey, I highly recommend it:
The book has been in print for many years and copies are available starting at about $11.00.
Maybe that trip was a Land Rover idea for Jeeps because a few years later two English Colonial Police officers made the reverse trip in a war-surplus Willys Jeep. They also wrote a book about it:
This book is a bit harder to find because it's been out of print for a long time and copies typically retail for over $100 but I managed to score a copy the other day on eBay for twenty bucks. Having read the Land Rover version of the expedition, I'm looking forward to reading about the Jeep version of the trip.
Here's a scan from the Jeep book. Check the post I linked to above, the Land Rover expedition took a very similar photo. Actually taking photos of vehicles driving alongside the Darjeeling train is pretty common, there's more info and photos I took on my expedition in that post.
BTW I wasn't in either a Jeep or a Land Rover when I did a trip to Darjeeling, I was in a Mahindra. We took the Mahindra up to Kurseong so I could take photos of the train along the way and then rode the train from there to Darjeeling. After spending a few days in Darjeeling we took the Mahindra all the way down the line to the plains of West Bengal, stopping to take railroad photos along the way. The goal of the trip was to write an article for a magazine and get great photos, which is why I didn't ride the train all the way - much easier to get great train photos when you're not on the train.