Lancaster Antiques has dated this Antique Railway Padlock Key to the 1910s.
We believe this is the London, Midlands and Scottish railway service from the early 1900's.

It is in good condition and the mechanism works well. The thickness can be seen clearly in photo 3 and it weighs about 528grams or half a kilo.
The padlock measures 11.5cm in length without the chain, it is approximately 8.5cm wide and 2.25cm thick.
Lancaster Antiques has dated this Antique Railway Padlock Key to the 1910s.
You can view the stock and full dealer information on the Lancaster Antiques Profile Page