Britain's Great Western Railway had the good taste to name a series of its most powerful passenger steam locomotives after Kings. The last such built rolled out of Swindon as King Stephen.
This morning, a bout of channel-surfing led me to a new Thomas the Tank Engine hour-long adventure called "King of the Railway". The King, or at least the protagonist, is named "Stephen". He's an 0-2-2 with a Rocket nameplate. (Yes, that one, but in this adventure the Duke of Sodor -- there's a full history of royalty and commoners that's probably a bit much for toddlers -- has it restored to operation to show guests around Camelot, er, Ulfstead Castle.) One sub-plot features a rivalry between "Gordon" (a Gresley A3, but NOT Flying Scotsman, who belongs to the Sodor Railways), and "Spencer" (a Gresley A4 that belongs to a private owner, which leads "Gordon" to question whether he's a Really Useful Engine). These products of Doncaster get into unofficial races (like those between the Century and Broad Way east from Engelwood) whilst denying that there is any racing going on. That is, until the two of them, racing on a four track stretch of railway, are overtaken by two special express trains from the mainland for the dedication of Ulfstead Castle as an historical attraction.
Those trains are in the care of "Caitlyn", loosely a Baltimore and Ohio Streamlined President Pacific, and "Connor", more evidently a New York Central Hudson as streamlined by Henry Dreyfuss.
That ought to settle, once and for all, who had the fastest passenger steam locomotives.