That very nice example of Neo-classic architecture is the headhouse of the old Curzon Street station in Birmingham. It was in railroad use for 128 years starting in 1838, and it wouldn’t surprise me if that was some kind of record for longevity among railroad buildings. Originally, it was the front of a dead-end station that had tracks under an open iron shed. After 1893, it was converted to freight use – and that made it one of the fancier freight around – and then it was finally closed for train use in 1966.
If you simply look at the building now, in isolation, “railroad station” is probably not what would come to mind. It’s not the architectural style, as there have been plenty of Roman-inspired stations. It’s the overall size and generally human scale of the building that, to us, masks its purpose. If you click on the second link above, there’s a drawing of the rear of the Buidling showing the platforms and shed, which were wider than the headhouse. Later station design would have made the headhouse bigger, both to hide the tracks and shed and to allow direct access from the interior space to each track. That’s one of the reasons station buildings were generally large: to span across the tracks.
At the time Curzon Street Station was built, railroads were new and designers (architects and, often, engineers who designed stations without architects’ involvement) were still figuring out what the requirements were for station buildings. This was a totally new type of use, where large numbers of strangers would collect and then leave, and would arrive as a group and then rapidly disperse. The ancient building types for large numbers of strangers were places they stayed, like theaters and churches. When faced with a new use, it took some time for architects to figure out what was needed for functionality, a process of design evolution made more difficult by the fact that rail traffic kept increasing, so the needs kept increasing.
The earliest examples of any new building type are often functionally awkward, regardless of their formal aesthetic designs, as designers struggle to understand the use requirements.