First to operate a locomotive in America-- the "Tom Thumb," in September, 1829.

First stone-arch railroad bridge in America--"Carrollton Viaduct," completed November 7, 1829.

First trip of a passenger car (horse drawn and locomotive drawn) in America, December, 1829.

First timetable advertisement-- The Baltimore American for May 23, 1830.

First railroad passenger and freight station--Mt. Clare, in 1829. (Rebuilt 1830.)

First dividend declared by a railroad company--January, 1831.

First double-track railroad-- Baltimore to Ellicott's Mills, February, 1831.

First to operate an 8-wheel passenger coach--Ross Winan's "The Columbus," put into service on July 4, 1831.

First railroad to operate a train at a speed of 30 miles per hour, on August 30, 1831.

First to use iron wheels on passenger cars--1832.

First to operate a railroad shop--Mt. Clare, 1833.

First locomotive turntable ( Elgar's) --Mt. Clare Shops, 1834.

First to use a baggage car--1834.

First railroad to Washington--August 24, 1835.

First railroad to secure a government contract for carrying the United States mails--January 1, 1838.

First railroad to use dining or "reflectory" cars--1843.

First telegraph line, Baltimore to Washington, built along B & O lines, 1844. (First message transmitted through Mt. Clare Station, May 24, 1844.)

First to use iron box cars, forerunner of present all-steel cars--1844.

First to test an electrically-operated locomotive (Page's)--April 29, 1851.

First railroad to reach the Ohio River from the Eastern Seaboard--December 24, 1852.

First railroad to offer through service from the Atlantic Coast to the Mississippi River--June 21, 1857.

First railroad to construct a grain elevator for the export trade--Locust Point, 1872.

First railroad to operate a railway express company--August 1, 1877.

First railroad to place an electric locomotive in regular service--June 27, 1895.

First railroad to operate a streamlined passenger train, Baltimore to Washington--May to August, 1900.

First railroad to place an articulated Mallet locomotive (Muhlfeld's) in regular service in the United States --1904.

First railroad in the United States to retain its charter name for a complete century--February 28, 1927.

First railroad to operate an air-conditioned car-- the diner, "Martha Washington," April, 1930.

First railroad to operate a completely air-conditioned train--the "Columbian," May. 1931.

First railroad to operate a streamlined diesel-electric locomotive in long-distance passenger service--the "Royal Blue," May 25, 1935.

First to offer scheduled carload freight service--inaugurated in 1947.

First railroad in the eastern United States to place Strata-Dome cars in regular passenger service--1949.