Robin Chittenden / View out of train on the Ceredigion The Vale of Rheidol Railway, Wales, UK. August.

Alan Williams / Steam train leaving Berwyn station beside the River Dee and the Chainbridge Hotel on the Llangollen Heritage Railway to Corwen North Wales, UK, September 2017.

Franco Banfi / An old steam locomotive, Circum-Baikal Railway, Trans-Siberian Railway, Irkutsk Oblast, Lake Baikal, Siberia, Russia.

Graham Eaton / A steam train enters Aberglaslyn Pass, alongside the river Glaslyn, near Beddgelert, Wales, UK June

Daniel Heuclin / Freight train driving along Union Pacific Railroad, Mohave National Preserve, California, October 2013.

Gary K. Smith / Steam train on the Heritage Poppy Line from Sheringham to Holt, with Weybourne Mill in background, Norfolk, UK, April.

David Shale / Starfish (Asteroid) with sensory and locomotive hydraulic tube feet extended. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

David Shale / Starfish (Asteroid) with sensory and locomotive hydraulic tube feet extended. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

David Shale / Starfish (Asteroid) with sensory and locomotive hydraulic tube feet extended. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

David Shale / Starfish (Asteroid) with sensory and locomotive hydraulic tube feet extended. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

Philippe Clement / Steam engine / locomotive at the Boat of Garten railway staion, Highland, Scotland, UK, May 2010

Nick Upton / Narrow gauge railway locomotive hauling wagons loaded with dried peat turves, passing rows of newly cut turves. Goldenstedt moor, near Vechta, Lower Saxony, Germany.

Paul Harcourt Davies / Old, rusting locomotive engine, taken over by nature on the old Peloponnese narrow gauge railway nr. Naupflion, Greece. March, 2015.