Every railway gun of the Second World War: the French guns captured in 1940, the German guns built from old battleship barrels, Schwerer Gustav at Sevastopol, Anzio Annie, the Soviet guns the Finns rebuilt and handed back, Britain's Boche Buster, and the one railway gun Japan owned. Every journey followed on the real railway lines, on the map.

0:00 Five Days in June
1:58 Why Put a Gun on a Train
3:34 The French Railway Artillery
7:13 The Emergency Programme
9:57 Across the Channel
14:45 Hanko
18:16 The Siege Guns of Leningrad
21:52 Gustav
27:02 My Steel Fist
29:10 Anzio Annie
32:08 Everyone Else
34:28 Killed From the Air
36:58 What Is Left

Sources:
Lexikon der Wehrmacht, Eisenbahn-Artillerie battery histories
Gerhard Taube, Eisenbahngeschütz Dora (1979)
Steven J. Zaloga, Railway Guns of World War II (Osprey, 2016)
US Army Center of Military History, Anzio Beachhead
V. I. Bragin, Pushki na relsakh (Soviet naval railway artillery)
Wikimaginot and artillerie.asso.fr (French ALVF regiments, 1939-40)
Royal Artillery 1939-45 (ra39-45.co.uk); Disused Stations, Elham Valley line
jaegerplatoon.net (Finnish railway artillery)
Photographs: Bundesarchiv, NARA, Imperial War Museums, NAC Poland, SA-kuva, Nationaal Archief, Gallica, waralbum.ru, Wikimedia Commons. The photographs were restored and colourised with AI.
Film: Die Deutsche Wochenschau (617, 705 and others) and US Army films, via the Internet Archive.