Explain the vestibule on steam locomotives

I often read about or hear about a reference to a ‘vestibule’ versus an open cab on a steam locomotive.

Any steam locomotive I have ever had the chance to look into, which is not many, I would say they were all ‘open’. In other words, the opening at the rear of the cab went from one side to the other, and there is a small opening between the cab and the front of the tender.

So I hope someone can tell me how to spot a vestibule, and perhaps define it.

And I see some cabs will have curtains between the back of the cab and the tender, while others do not.

Up here in Canada, I could not imagine operating a steam locomotive in the winter, without some for of curtains.

Any help there?

In Canada, both CN and CP as well as Northern Alberta, had “vestibule cabs” to protect crews from the cold. Notable US users of vestibule cabs were Alaska,Great Northern,(SP&S?)and P&LE. Most railroads had curtains that would enclose the cab in varying degrees, but the crews just bundled themselves up, and went on about their work. Vestibule cabs, however were introduced in the US a bit late(1928 on GN). By the time P&LE adopted vestibule cabs,(1947) dieselization was right around the corner. CN predecessors Canadian Northern, Canadian Government Railways and Grand Trunk first had vestibule cab equipped Mikados in the early years of WWI! (1916 for The National Transcontinental and CNor) CP was right behind, with their P2 Mikes, starting right after WWI. They weren’t “pretty” but, they were appreciated by crews lucky enough to bag one for their jobs. They were cleaner than their conventional sisters as well. But, cold is still cold, and no steamer I know of has been described as warm in winter!

Having never experienced the environment of a steam locomotive cab, I had wondered about it and thought it would have been quite warm in any season. Thanks for clearing this up for me.

The only currently running engine I can think of off hand w/ a vestibule cab (also called “all weather cabs”) is the Milwaukee 261. If you want weather related horror stories try to imagine what it must have been like switching the produce sheds in California’s Imperial Valley in an August afternoon with an SP Consolidation!

The identifying feature of a vestibule cab is the presence of side doors behind
the cab side windows. They are installed where the typical roof overhang
at the rear of a cab is located. These enclose the sides for weather protection.
Harder to see is the solid back wall between the loco and tender, usually
equipped with a walk-through door to the tender. Vestibule equipped locos
were usually oil-fired or stoker-equipped due to the difficulty of hand firing.

Not to mention the extra cost of a vestibule cab versus a “conventional” cab!