Rare antique rail workers jacket - British 1920s? Beautiful condition

I believe this is an original Railroad worker (‘shunters vest’) ‘sleeved waistcoat’. British railways? Super condition.  The waistcoat is made from black wool. It features a five button front and the three front pockets. The sleeves and back are charcoal cotton. The inside of the jacket is lined with natural cotton.  There is a stamp on the inside but it’s not readable. Research tells me it’s likely to date back to around the 1920s, so an antique piece. Measures: Chest - 18.5” pit to pit Shoulder to shoulder - 15” Collar to lowest point of hem - 22.5" Sleeves -21” A lovely example of British workwear in great condition. Could easily be worn today - fits woman uk 8