After 1936, when one of its major leases was dissolved, it continued operating streetcars and, increasingly, buses in certain Connecticut cities until 1976, when its assets were purchased by the state government.

That company, which operated local lines in the city of Stamford, was in bad shape financially, and the owners of a majority of its stocks and bonds, wishing to get rid of their investments, found a willing buyer in the New Haven.

This agreement was modified on July 18, 1901, by which time Sanderson & Porter had gained control of the Worcester and Webster Street Railway and Webster and Dudley Street Railway in Massachusetts, and subscribed to the stock of the Thompson Tramway, which planned to connect the two segments, thus forming a continuous line between Danielson and Worcester, Massachusetts.

The Stamford Street Railroad also, in late 1903, opened a connection with the Greenwich Tramway, thus completing the trolley link between New Haven and the New York state line.

[3] The effect of these transactions was to give the New Haven control of a large system of electric railways in Connecticut and Massachusetts, many of them connecting with each other.

[13] A continuous route between Stratford and Waterbury via Derby and Seymour was completed in 1907 by lessor Naugatuck Valley Electric Railway.

[21] This left the New Haven as owner of all the property operated by the Connecticut Company except for that owned by the Connecticut Railway and Lighting Company, as well as the portion of the coastal line in West Haven owned by the West Shore Railway, which had been leased to the Fair Haven and Westville Railroad prior to its acquisition in 1904,[22] and the short South Manchester Light, Power and Tramway Company, similarly leased to the Hartford, Manchester and Rockville Tramway.

[23] The largest expansions of the system were made by electrifying various existing steam lines of the New Haven and running trolleys over them, providing connections in 1906 from Middletown west to Meriden and north to Cromwell, connecting at the latter point with a new rural trolley line to Hartford, and a link between Norwich and Central Village.

The segment from Middletown via Westfield to Berlin was also electrified[24] for use by the Connecticut Company, but was later operated exclusively by the New Haven using larger passenger cars.

The purpose of retaining these lines was to keep the Connecticut Company an intrastate carrier, hopefully not subject to Interstate Commerce Commission jurisdiction.

[27] In July 1914, the Attorney General of the United States filed suit against the New Haven, citing violations of the Sherman Antitrust Act in relation to its effective monopoly of steam and electric railways and water transportation in New England.

[31] The Rhode Island Company was similarly reorganized into the United Electric Railways in 1921, losing its line into Connecticut in the process.

[37] Just prior to the return to New Haven control, in early November 1925, the state authorized the system's first major abandonment and replacement with intercity buses, on the portion of this division north of Norwich.

[39] The Hartford Division was completely converted to buses on July 26, 1941,[40] but trolleys continued to run on the streets of New Haven until September 25, 1948.

[45][46][47][48] The Connecticut Company itself left New Haven control in June 1964, after defaulting on federal flood loans, and was reorganized under the same name and sold by the United States for $3,225,000.

[50] In October 1972, the Connecticut Railway and Lighting Company, then operating buses in and near Bridgeport, Waterbury, and New Britain, ceased all service because of lack of money.

[51] The next month, Connecticut Company drivers and mechanics went on strike, and service, then concentrated on Stamford, New Haven, and Hartford, did not resume until the state began subsidizing it in March 1973 with federal assistance.

A third line east to Middletown over New Haven trackage was part of the Middletown Division, which comprised eight radial lines in and around that city, including service southwest to Middlefield, northeast over the Connecticut River to Portland, and north, partially over New Haven trackage, to Rocky Hill and the Hartford Division.

One branch headed northwest through Willimantic to South Coventry, while the other entered New Haven trackage from Taftville to Central Village.