491 still has a spark screen on its stack, indicating it still has a Master Mechanic Front End in the smoke box. According to the AFE book, 491 received a Cyclone Front End on 10/31/42. As the flying Rio Grande debuted in 1939, the date is somewhere in the middle. When the Cyclone Front Ends were installed in the smokebox, the stack screens disappeared.
Well...... according the AFE book BOTH 490 and 491 got Cyclone Front Ends in 1942. So.....where does this leave us?
Edited 1 time(s). Last edit at 03/16/2020 08:14PM by Earl.