Records in this series are comprised of correspondence, memoranda, notes, reports, engineering drawings, photographs, and prints.

The numerically arranged correspondence files of the Great Northern Chief Engineer's office provide basic documentation concerning all facets of the engineering work carried on by the company, including civil engineering (rail line and road bed, bridges, tunnels, and culverts), structural engineering (buildings and towers), and mechanical engineering (rolling stock and motive power, equipment, machinery, and fuel). The correspondence also documents the operations of the engineering department itself.

The files, which are not complete, date largely from the 1950s, although many contain materials from the early decades of the century. A list of file titles follows the box/location list; there is no index to topics contained in the files.

The lists include dimensions of bridges, construction dates, and mile-post locations.

Record of bridges, by division, listing the name of station, bridge/culvert number, kind of bridge/culvert, length and height details, date of erecting/renewal, and remarks.

The volumes in this series record summary information on the AFEs (authorities for expenditure) issued by the chief engineer's office. AFEs were issued for all work projects involving construction of, or improvements to rail line or structures. The 15 volumes located in the first 3 boxes form the chief engineer's record of AFEs issued during the 1906-1916 period. Each volume contains AFE descriptions for a different division, and the volumes are arranged geographically (East to West). The entry for each AFE includes the date it was requested, the number assigned by the chief engineer, a description of the project, the estimated cost, the number assigned by the president's office, the date it was approved, the date work was completed, and the actual report (if different). AFEs are listed by station, rather than by number.

The remaining 2 volumes (box 4) are a separate series of AFE registers kept by the president's office, and covering the 1907-1913 period. Although they contain basically the same information contained in the chief engineer's set, it is all organized by the president's AFE number, rather than by the locality of the work. There is, however, an index to projects by location in each volume.

This series of records indexes the Great Northern chief engineer's file of authorities for expenditure (AFEs). The AFE files document all railroad construction projects, including the erection and improvement of buildings and other structures, and additions and betterments to the railway line itself. The index entries summarize each AFE project, giving information on dates, work performed, and costs charged.

The indexes are organized by place. The 1888-1906 indexes are in volume format; each volume indexes a short span of years and is organized by division, thereunder by station name and branch line. The indexes for 1907-1970, however, are in card format. The cards (5 in. x 8 in.) are arranged almost exclusively by station name, though there are some cards for particular branch lines. The unbroken alphabetical sequence of station names means that there is no organization by line division or any other natural grouping. Following the alphabetical sequence of station names is a small group of cards (box 11) indexing system AFEs, those being work projects that were not confined to the locality of any particular station.

The cards, formerly in a file cabinet, have been repacked into boxes. Within each box they are in banded segments to make them easier to handle. There are also frequent index tabs showing the location of larger stations to help users orient themselves.

Volumes provide wage and salary data on all Engineering Department employees for the inclusive period. For each month's payroll the records list the employee's name and occupation, pay rate, and number of days (hours) worked.

This series consists of architectural drawings (including elevations, cross-sections, floor plans, and details) of depots, engine houses and other shop buildings, water tanks and other storage buildings, railroad workers' housing and miscellaneous structures. The drawings are grouped by size but the series appears to have been assembled from various older series with no apparent logical order. Some of the drawings are standard plans and some are for specific sites.

The depot drawings include passenger stations, combined passenger and freight depots, shelter stations, immigration buildings, remodeling plans, freight houses, platforms, and facilities for cattle, sheep, and fruit. Shop structures include engine houses, wheel houses, power houses, and scrap bins. Storage buildings include structures for storing supplies and equipment: coaling facilities; tanks for water, oil, and gasoline; buildings for sand and ice; root cellars; and storehouses for tools, hand cars, hoses, and storm sash. Workers' housing includes section houses, section foremen's houses, bunk houses, cottages, and offices.

There are also drawings for: privies, toilets and septic systems; Japanese-style structures for a recreation park at Liberty Lake [in the vicinity of Spokane, Washington?]; electrical substations, transformer houses, and distribution houses near Spokane, Washington; Post Office equipment at the Seattle Terminal; and furniture such as ticket cases, station desks, and telegraph operators' tables.