Despite being widely touted as the longest trains in the world, the up-to 2.5 kilometre-long freight trains which bring iron ore to Nouadhibou, Mauritania may not be particularly unique in their length.

On the day these images were captured, the longest train we can see at Nouadhibou (as measured with Google Earth’s measuring tool) is approximately 1.97km long.

In the past we’ve seen some other extremely long trains, like these 2.2 kilometre-plus coal trains in Wyoming, and over in Pennsylvania there’s a freight train which measures 2.98km from one end to the other - a whole kilometre longer than those in Mauritania.

However, all these trains could have been put to shame by the locomotives of Port Hedland, Western Australia - if only there had been any really long ones around when these images were taken.

Sadly, the longest I could find here was a distinctly average 2.2km, which falls far short of their longest ever, which purportedly consisted of 8 engines, 682 cars and totalled a staggering 7.3km - which quite probably would have made it the longest train of all time.

So, has anyone got a longer one to show us?

For more like this, see our posts on Incredibly Long Trains and Bailey Yard. Thanks to Helge Fahrnberger, Romke Soldaat and the Keyhole users.

Lots of things to see here in Yellowstone National Park, it’s just a pity we can’t see any of the grizzly bears, wolves, or free-ranging herds of bison and elk!

First up is the world famous Old Faithful Geyser, it’s in the middle the concentric walkways you can see in our thumbnail. Old Faithful was so-named because of the reliability of its eruptions, which are currently happening about every 65 minutes, unfortunately it’s not erupting in our picture. Of the 1000 or so geysers in the world, about half of these are in Yellowstone. If you look closely on the walkway, I think you can actually see people watching for an eruption.

Next up are these fantastic waterfalls at the mouth of the Grand Canyon of the Yellowstone, whose yellow-coloured stones gave the park its name.

Finally we have the awesome Grand Prismatic Spring which is the largest hot spring in the United States, and the range is colour shown here is incredible. The blue-white pool to the Northeast is Excelsior Geyser, although it’s been dormant since 1990.

The colours in the spring are produced by different species of thermophilic bacteria that live in the narrow temperature ranges formed as the waters of the hot spring naturally cool farther from the heat source. The reddish bacteria at the outer edge survive in the coolest water with the yellowish and greenish bacteria living in progressively hotter water. The water in the central blue area of the spring is too hot to support any of the bacteria.

Lots and lots more information about Yellowstone National Park is available on Wikipedia, and the official Yellowstone site even has a webcam of Old Faithful .

Thanks to (and this may be our longest thanks list yet!) Brian Ralli, Rick, Tom Gula, Balazs Ganszky, MIke, dx, CosmicPenguin, Chris Prince, Rosewood, Jeff, spaz, Ballard, Brian, JasonRene, Corey Vilhauer, Benjamin, Peter Szabo, Kyle, Tim, Chris Shinkle, Dick Nielson, Wayne, Ray Bellis, Zoltan Horvath, Jens Kilian, mark, J. Gable, Kimon Berlin, Laura Vance, Sparky Treewaller, Matt, Don S, Jared Roberts, Fakus Namus and last but by no means least Rebecca Ray. Thank you everyone!

Here in Powell, Wyoming, they really really love baseball!

Thanks: Steve Rot

Looks like these trains are stopped at a level crossing on the Burlington Northern railroad track in Wyoming. The Northern one is chopped off by some low-res imagery, but scroll south to see just how incredibly long they are! Amazing.

Thanks: tamat

Update

In the comments, Eric Smith said:

These are unit coal trains, typically 100-115 cars long. These were probably going from/to the Powder River Basin in Wyoming, which is just north of the photo you found. Here is the loading loop, large enough to run one of these trains in a circle.

You can see that the image was taken just after the two ends of the train passed each other, as the black carts are fully loaded with coal.

Steve Rot sent us this cool link to somewhere that looks very like Mars (although it’s actually in North Wyoming), thanks Steve!

Devils Tower is a a monolith that rises to a height of 1,267 feet and featured prominently in the Steven Spielberg film Close Encounters of the Third Kind (where it was reproduced in mashed potato).

Thanks: xylon, Sally, many others.