While it is deceptively easy to read many other letters into this monogram, what appears to be true is an elongated superior "I" conjoined at its' center by an "M", thence super-Imposed above a double-wide "R" which is slightly shifted above that center point in order to set it out. Reed & Barton's "Royal" pattern is essentially a twin sister to the "Cecil" pattern, both recieving the patent granted date of February 7th 1899.
Interestingly, Cecil was employed both by Chicago & Alton railroad and Southern Pacific railroad with topmarked initials. Together with the "Iron Mountain Route" and a bridge line across the Texas & Pacific, these four roads formed what was once known as the "True Southern Route to California" from Chicago. (This was superceded by the "Golden State Route" across the Chicago Rock Island & Pacific R.R. by 1902-3.) Royal has turned up employed by the Palace Hotel which would have marked the end of the route in San Francisco (via transferred through Pullman sleepers leaving Los Angeles on other trains).
The Iron Mountain was controlled by Missouri Pacific, but held as a separate entity with an independent identity. A joint useage china pattern, Maddock's Pottery Lamberton Works in Trenton N.J., has the Missouri Pacific logo placed opposite an "Iron Mountain Route" box logo providing proof that this name was used in dining services rather than the railroad's official initials. A check of paper ephemera provides no exact match to this monogram, but does show the extended "I" was used.
Any additional information might help to determine if this is in fact a lost and undocumented silverware logo for this era.