the New York Central railroad's 4-8-4 "Niagara" could accelerate to 90 MPH in just 2 minutes with a 20 car passenger train

and there is a video that Marc sent me, (thank you Marc!) which mentions but does not show, this "Niagara" pulling something called an "eye test car" and the video narrator says that there was only one of those, a new thing because of a new requirement the New York Central had made that the engineers be tested for visual acuity 

the Engineer pointing to his eyes in a joking manner as his locomotive is pulling the company eye test car. From the Herron Rail Video show "Niagara’s Last Stand, NYC Steam 1953 – 1955"

I looked around and yet could NOT find ANY thing about the "eye test car"

But enjoy this early 50s steam locomotive 90 second video, it's great sound and visual quality is superb https://www.facebook.com/HistoricSteamGiants/videos/523930973388590/

https://www.facebook.com/HistoricSteamGiants/videos/1639601459962364/?fs=e&mibextid=wwXIfr&rdid=22Lxe614OOdwMZ4P#

https://www.reddit.com/r/MachinePorn/comments/y84mz2/one_of_the_most_efficient_steam_locomotives_ever/

https://nycshs.omeka.net/

https://www.facebook.com/groups/21550063750/