The North Carolina Transportation Museum occupies the former Southern Railway Spencer Shops, the railroad's largest steam-locomotive servicing facility, built beginning in 1896 roughly midway between Washington, D.C., and Atlanta. Both the shops and the town of Spencer were named for Samuel Spencer, Southern Railway's first president. By 1932 the complex performed daily repairs on around 75 steam locomotives and could turn out a completely rebuilt engine each day, employing roughly 3,000 workers at its peak. Diesel power ended the need for the steam shops, which wound down through the late 1970s.

The museum was founded in 1977, when Southern Railway deeded about 4 acres (1.6 ha) and three buildings to the State of North Carolina; a further 53 acres (21 ha) followed in 1979, and the site now covers roughly 57 to 60 acres. Its first exhibit opened in 1983, and the museum grew with the 1996 opening of the relocated 1898 Barber Junction depot, now the Visitor Center, and the renovated Bob Julian Roundhouse. Today it holds the largest collection of rail relics in the Carolinas and averages about 80,000 visitors a year.

The centerpiece is the 1924 Bob Julian Roundhouse, the largest surviving roundhouse in North America, with 37 stalls arranged around a 100-foot (30 m) turntable recognized as a Historic Mechanical Engineering Landmark. Nearby, the 1905 Back Shop, two football fields long and about two and a half stories tall and marked by its three-foot "Be Careful" lettering, once handled complete steam-locomotive overhauls.

The 37-stall Bob Julian Roundhouse fanning out around its 100-foot turntable is the museum's signature shot, strongest with locomotives spotted on several tracks; the turntable ride puts you at its center. The massive 1905 Back Shop, two football fields long with its three-foot "Be Careful" lettering, makes a dramatic wide-angle subject. The 1898 Barber Junction depot and the line-up of operating diesels in Southern and Norfolk & Western liveries are also strong. Interior roundhouse lighting is mixed, so a higher ISO or steady support helps; ask staff about restrictions during special events.

The roundhouse displays an unusually deep roster of Southern and southeastern motive power. Operating diesels include Southern Railway EMD E8A No. 6900 (built 1951 as No. 2923, in Southern's green-and-aluminum livery), Southern FP7 No. 6133 (EMD, 1950), Southern GP30 No. 2601 (EMD, 1963) and Norfolk & Western GP9 No. 620 (EMD, 1958). The collection also holds Atlantic Coast Line E3A No. 501 (EMD, 1939), the only surviving example of its type, and ex-Amtrak F40PH No. 307 (EMD, 1979).

Steam and industrial locomotives on display include Graham County Railroad three-truck Shay No. 1925 (Lima, 1925), Seaboard Air Line 2-10-0 No. 544 (Alco Brooks, 1918), Southern 2-8-0 No. 542 (Baldwin, 1903) and Atlantic Coast Line 4-6-0 No. 1031 (Baldwin, 1913). Historic passenger equipment includes James B. Duke's private car "The Doris," the ornate "Loretto" once owned by steel magnate Charles M. Schwab, and Southern Railway car No. 1211, a 1917 Pullman partitioned under Jim Crow segregation laws and added to the National Register of Historic Places in 2022.

Beyond rail, the Bob Julian Roundhouse holds aviation exhibits and a full-size replica Wright Flyer, while the Flue Shop's "Bumper to Bumper" exhibit gathers antique automobiles including several Ford Model Ts, a Model A and a 1907 Ford Model N. The museum keeps no operating steam of its own but has hosted notable visitors, including the on-site restoration of Norfolk & Western 611 in 2014 to 2015 and the 2014 "Streamliners at Spencer" gathering.

Visits begin at the 1898 Barber Junction depot, the Visitor Center where tickets, train boarding and the site shuttle are based. From there a walking path links the exhibit buildings spread across the roughly 57-acre site, so comfortable shoes and time to walk are useful. A self-guided audio-tour app is available for Apple and Android devices.

The signature experience is a roughly 25-minute train ride pulled by a vintage diesel locomotive around the historic grounds, offered on a seasonal schedule. Limited locomotive-cab and caboose rides are sometimes available at the train crew's discretion for an additional fee, and turntable rides on the 1924 turntable run $1 per person (ages 3+). Note that the cab and caboose are not ADA accessible.

Most exhibit buildings and restrooms are accessible, with a wheelchair-lift shuttle on site and the train ride accessible with about 15 minutes' notice; entry to many vintage rail cars is not. Plan roughly two to four hours. The museum also hosts major seasonal events, including Day Out With Thomas, THE POLAR EXPRESS and the Easter Bunny Express, which use special schedules and pricing.