Re: Steam Locomotive Overhauls

In June 1918 the USRA set up a standard classification of repairs to locomotives and tenders. There are five classes of repairs as follows:
CLASS 1
New boiler or new back end. Flues new or reset.
Tires turned, or new.
General repairs to machinery and tender.
CLASS 2
New firebox, or one or more shell courses, or roof sheet.
Flues new or reset.
Tires turned or new.
General repairs to machinery and tender.
CLASS 3
Flues all new or reset (superheater flues may be excepted).
Necessary repairs to firebox and boiler.
Tires turned or new.
General repairs to machinery and tender.
CLASS 4
Flues part or full set.
Light repairs to boiler or firebox.
Tires turned or new.
Necessary repairs to machinery and tender.
CLASS 5
Tires turned or new.
Necessary repairs to boiler, machinery, and tender, including one or more pairs of driving-wheel bearings refitted.
General reapirs to machinery will include driving wheels removed, tires turned or changed, journals turned, if necessary, and all driving boxes and rods overhauled for a full term of service.
Running reapirs unclassified.
Locomotives receiving class 1, 2, or 3 repairs must be put in condition to perform a full term of service in the district and class of service in which they are to be used.
Locomotives receiving class 4 repairs must be put in condition to perform not less than one-half term of service in the district and class of service in which they are to be used.
Locomotives receiving class 5 repairs must be put in condition to perform not less than one-fourth term of service in the district and class of service in which they are to be used.
Naturally, these classifications have gone out with regular steam service. The work, however, remains the same; just not as scheduled as it used to be.
Hope this helps in some manner.