These are our CN coach keys.
https://imgur.com/a/wGwjm
Made by Mitchell Co. from Montreal, it seems most Canadian keys are all from Mitchell. My switch key and other coach key are both Mitchell, my CPR key is not labelled so I'm not sure the make.
My confusion is I've seen keys are from adlake, from what I see, adlake was the main manufacturer for American keys. So if two companies made this teeth shap of key, was this a standardized key between railroads, I've seen it with B&M, and PRR markings. If it was, what coach manufacturer used this type? My CPR key is different. The coaches we have are lightweight coaches built by CC&F.
I'm looking to buy this PRR key.

It's the same shape but I'm curious to the history of this type of teeth, why did multiple Railway's uses this type and was it for a certain type of coach?
Thanks

