Service← Previous revisionRevision as of 20:34, 13 November 2026 Line 92: Line 92: === Service === === Service === The M class would prove to be a mainstay of N&W motive power, working in mainline, transfer, switching, and branch line service. Many members of the class would undergo modifications over the years, such as the addition of higher-capacity [[Tender (rail)|tenders]], installation of power reverse gear, [[Superheater|superheating]], and the replacement of the original Stephenson [[valve gear]] with that of the Baker type. Popular in service, crews would come to affectionately nickname the locomotives ''Mollies'', a moniker which stuck until their retirement in the late 1950s.{{Cite magazine |last=Dressler |first=Thomas |date=August 1995 |title=Norfolk & Western's remarkable 4-8-0s |url=http://www.railfan.com/a081995.html |magazine=[[Railfan & Railroad]] |publisher=[[Carstens Publications]] |archive-url=https://web.archive.org/web/19980508103408/http://www.railfan.com/a081995.html |access-date=November 10, 2022 The M class would prove to be a mainstay of N&W motive power, working in mainline, transfer, switching, and branch line service. Many members of the class would undergo modifications over the years, such as the addition of higher-capacity [[Tender (rail)|tenders]], installation of power reverse gear, [[Superheater|superheating]], and the replacement of the original Stephenson [[valve gear]] with that of the Baker type. Popular in service, crews would come to affectionately nickname the locomotives ''Mollies'', a moniker which stuck until their retirement in the late 1950s.{{Cite magazine |last=Dressler |first=Thomas |date=August 1995 |title=Norfolk & Western's remarkable 4-8-0s |url=http://www.railfan.com/a081995.html |magazine=[[Railfan & Railroad]] |publisher=[[Carstens Publications]] |archive-url=https://web.archive.org/web/19980508103408/http://www.railfan.com/a081995.html |access-date=November 10, 2022 |archive-date=May 8, 1998}} |archive-date=May 8, 1998}} Following the initial success of the class Ms, the N&W would order more 4-8-0s of nearly identical design in the form of the M1s in 1907. These differed in their use of Walschaerts valve gear and [[piston valves]] in place of [[slide valves]]. This design change, however, severely affected the locomotives’ performance, largely due to a poorly-executed design. The valves’ centerlines, being offset from those of the pistons, resulted in excess running gear wear and improper valve timing. Unsurprisingly, as older motive power on the N&W would be phased out, the M1s were among the first to go. Following the initial success of the class Ms, the N&W would order more 4-8-0s of nearly identical design in the form of the M1s in 1907. These differed in their use of Walschaerts valve gear and [[piston valves]] in place of [[slide valves]]. This design change, however, severely affected the locomotives’ performance, largely due to a poorly-executed design. The valves’ centerlines, being offset from those of the pistons, resulted in excess running gear wear and improper valve timing. Unsurprisingly, as older motive power on the N&W would be phased out, the M1s were among the first to go. Design shortcomings would plague the subsequent class of 4-8-0s, the M2s, as well. From their arrival in 1910, issues with poor riding qualities and steaming were apparent. Though utilizing a larger boiler than either the Ms or M1s, the M2s possessed a relatively small heating surface area in the firebox, resulting in considerable difficulty in maintaining steam. In spite of the issues (along with subsequent unsuccessful modifications), the M2s lasted in service for considerably longer than the M1s, being among the few larger examples of non-articulated freight power owned by the N&W. The last examples lasted in service until the late 1950s. Design shortcomings would plague the subsequent class of 4-8-0s, the M2s, as well. From their arrival in 1910, issues with poor riding qualities and steaming were apparent. Though utilizing a larger boiler than either the Ms or M1s, the M2s possessed a relatively small heating surface area in the firebox, resulting in considerable difficulty in maintaining steam. In spite of the issues (along with subsequent unsuccessful modifications), the M2s lasted in service for considerably longer than the M1s, being among the few larger examples of non-articulated freight power owned by the N&W. The last examples lasted in service until the late 1950s. ==Experiments== ==Experiments==