Yeah I did bit more exploring there on that site... incredible.... Railway League yes... but then there was also the Telephone League... Northern Electric Team's & so on.... much of it Montreal-centric.... and absolutely was top tier hockey running from about 1902 through the 20's only breaking for the War. Played at the Montreal Forum, clearly a big deal & popular. Guys like Joe Malone involved in addition more than a dozen others as you mention....
One of my favorite stories being the player (name escapes me) who played in the NHL and off-season worked as a Stoker for CNR, shoveling coal into the fire box in the locomotive car that fueled the boiler.... and when he got hungry....
fry up a steak on his shovel.......... something he then carried over to his playing days as a Senior... doing the same on the pot bellied wood burning stoves that heated the shacks & pavilions adjacent to outdoor rinks back in the day used as dressing rooms, keep-warm rooms.... unreal. Guys having his pre-game meal IN the dressing room.... steak on a shovel.