I've taken overnight train rides ranging from $40 to $9,000 a ticket. Here's how I'd rank them from worst to best.

Business Insider's reporter has been on six overnight trains in the US and Europe in accommodations ranging from seats to private cabins.Joey Hadden/Business Insider

• I've spent 120 hours on overnight trains in the US and Europe testing out different accommodations.
• The best sleeper train accommodations provide privacy, amenities, space, and luxury.

I've spent 120 hours traveling on overnight trains to sample a variety of accommodations available in the US and Europe.

After six nights of sleeping in seats, bunks, and private cabins in five different countries, I've found that the best accommodations offer privacy, amenities, space, and perhaps a taste of luxury.

Here's a ranking of every sleeper train accommodation I've tried based on my comfort and overall experience during the journey.