The D&RGW ON was much earlier than the second Midland plow. The ON was built as the #2 in 1899 just after the OM.
It was close to the Crystal River plow that became D&RGW OO
#56 WP&Y 1 1899
#57 Erie 3413 1900
#58 CM B 1900
#59 C&S 03 (99201) 1900
#60 Crystal River AB2 1900 Became D&RGW OO
#61 WP&Y 2 1900
#62 Buenos Aires & Valparaiso FCTA TA1 1900
#63 D&RGW 12; (071) 1903
#56, 59, 61 and #62 still survive.
Info on the Midland Plows:
#10 Cooke 12/1887 Colorado Midland Old 08; A 1899; 123,700 lbs + 37,900 tender;
1st use 11.14.1891; Used on Moffat Feb
1905. cleared CS&I trolly line to Manitou
Dec1913; Midland Terminal A 1922;
Scrapped MT Colorado Springs 1949;
9’ rotary blade; 17x20 cyl
#58 Schenec 1/1900 Colorado Midland Scoop B; $17,300 new; 133,500 lbs + 38,400
tender; 1st use 4.26.1900; Used on Moffat
Apr 1905, Damaged on Aspen Br feb ’12,
used Cripple creek lines Dec 1913; Sold
1922; ARR records say put into service at
Anchorage 1918; ARR paid $37,328.80,
Wrecked heavily Spring 1942 OOS for a
year; Alaska Engineering Commission
1945 Alaska RR used sporadically after
1945, retired 1964
Scrapped ARR 1968; 11’ rotary wheel
ARR 2 in later pics shows fan style wheel
which some records indicate came from ARR 1.