This series consists of Alteration Forms of the Rolling Stock Branch, later Mechanical Branch. The forms were issued in triplicate and copies were distributed according to need, to the Drawing Office, Workshops Manager, Production Engineer, Foreman Steel Car Shop, Diesel Inspector, Workshops Inspector, Motive Power Engineer and Foreman Diesel Shop (Mechanical). They served as a record and instruction of alterations which were required to be made to parts of locomotives and other rolling stock in use by the Tasmanian Government Railways, later AN Tasrail. No alteration was to be carried out without the authority of a duly completed Alteration Form signed by the Mechanical Engineer or his representative.

The form originated in the Design Office and specified the alteration required to be undertaken, assigned a priority to be given and advised relevant drawing numbers. The form also gives details of the class of stock affected and was signed by the Chief Engineer. The form was then sent to the Production Office where Job Numbers were allocated and then to the relevant Workshop for the actual alteration to be carried out.

The Alteration Form continued in use although it was converted to electronic form on the Traffic Management Information System (TIMS). There was a significant decrease in the number of Forms issued during the mid 1990's as ANTasrail largely ceased undertaking modifications within its own workshops.

These records are part of the holdings of the Tasmanian Archives