Since the railway construction boom of the 19th century, have any new rail corridors been built since then?
Without doing a ton of research, I can think of several:
CN York & Halton subs; 1950s-60s
Central BC (Pacific Great Eastern then BC rail then CN); all since 1912,much since WWII
ONR; northern sections since early 1900s into the 1920s
Algoma Central; northern sections early 1900s
CP Mactier & Parry Sound subs; early 1900s
I imagine there are more.