Railroad rail sizes
Unknown Turnbuckle
Ma and Pa Flatcar

Resources
Utah Rails (in-depth historical information about railroading in Utah)
Wikisource - Steam Locomotive Construction and Maintenance
Hawkins Rails
Wabtec Conventional Brake Rigging photos of real, contemporary parts, no drawings
CFR 49 Part 231 Federal Railroad Safety Appliance Standards
Car builders' dictionary (archive.org)
Hand Brake Wheel. 44, Figs. 287, 288 ; 15, Fig. 291 ; 8, Fig. 364; Fig. 481. A wheel attached to the upper end of the brake shaft, by which the latter is turned to apply the brakes by hand.
Car Builders Cyclopedia
The Westinghouse Air Brake System: A Complete and Strictly Up-to-date Treatise Containing Detailed Descriptions and Explanations of All the Various Parts of the Westinghouse Air Brake, Including the 8 1/2 Inch Cross-compound Air Pump. No. 6 ET Equipment. High Pressure Control Schedule U. The K Triple, L Triple and LN Equipment. Combined Automatic and Straight Air Brake, and the 1 1/4 Inch Pump Governor 1911
Air brake catechism and instruction book on the construction and operation of the Westinghouse and New York Air Brakes 1908
The Westinghouse air-brake handbook; a convenient reference book for all persons interested in the construction, installation, operation, care, maintenance, or repair of the Westinghouse air-brake systems, or in the control of trains by means of the air brake 1913
American Car and Foundry Collection (archive.org) (see local)
Air-brake pumps ; Triple valves and brake valves ; Air brake troubles ; Operating and testing trains ; Foundation brake gear ; Air-signal system ; High-speed brake v.26-B
Heritage Rail - Journal boxes and their inspection
GE 20 and 23 Ton Box Cabs
GE 25 Ton Switcher
Southern Ry transfer cabooses in New Orleans