At peak size in the late 1910s, it operated 547 streetcars over 252 miles (406 km) of track, carrying 69.8 million annual passengers over 40 routes.

[1]: 46  In 1927–28, as part of the New Haven's modernization program, the company built a new carhouse and bus garage on Grove Street near the Rural Cemetery.

[5]: 136 [44] Staring in 1893, the main powerhouse for the city lines was a 5.65-megawatt (7,580 hp) steam generating plant located on Fremont Street in Worcester.

[3]: 686  With the expansions and acquisitions of the early 20th century, the WCSR had additional steam generating plants for suburban lines located in Millbury, Holden, Charlton City, Berlin, Northborough, and Leominster by the 1910s.

[46] Its four rotary converters, with a combined capacity of 7 megawatts (9,400 hp), provided 600 volt direct current power to the streetcar lines.

[60] It obtained ownership of the company's power station and was criticized for selling electricity and renting property to the WCSR at inflated rates.

[63][64] It found that only a small part of the Traction Company was owned by Worcester residents and that it had misled the public about the sources of funding for the system's electrification.

[82] The first decade of the 20th century was a "period of rapid consolidation" for the street railways in Massachusetts as the city systems purchased suburban lines.

[53]: 30  The line ran primarily on the Upper Post Road between Spencer and Webster Square; within Worcester it followed Cambridge, Exeter, Fremont, Canterbury, Hammond, Southbridge, and Portland streets.

This allowed suburban cars to circle the Common or be through-routed with other lines, rather than the previous time-consuming process of changing ends to reverse direction.

[2]: 73  On June 21, 1906, the New Haven created the New England Investment and Securities Company (NEISCo) as a "voluntary association" (trust) in an attempt to circumvent the law.

[51]: 986  It was intended as part of a through route between Worcester and Hartford, Connecticut – which did not have a direct railroad line between them – that would also include the Southbridge and Sturbridge.

They intended it to be the Massachusetts portion of an 'air line' following a nearly-direct course between Hartford, Connecticut, and Worcester, with a branch from East Brimfield to Springfield.

[178][179] Within several months, the New Haven-controlled Springfield and Eastern Street Railway sought permission to extend east from Monson to Fiskdale to connect with the Worcester and Southbridge.

[207][109]: 1279 [208] The Consolidated acquired the Woonsocket Street Railway and three adjoining lines in November 1906; it later became part of the Rhode Island Company.

[51]: 985 [218][101]: 13–15  Its route ran northeast from Westborough to Marlborough via western Southborough on a combination of rural highways and private right-of-way.

[270][109] On September 29, 1902, the Webster and Dudley was in turn leased to the Worcester and Connecticut Eastern Railroad (W&CE), a New Haven-controlled holding company.

[290] The intercity streetcar network in Massachusetts was largely complete by 1907, and no further rural lines were built by the WCSR or the companies it acquired.

[333][332] The Boston and Worcester Street Railway ceased using WCSR trackage on January 15, 1931, when it converted to buses west of Framingham.

[342][346] The Summit Line was converted to buses on July 17, 1937, allowing a road bridge carrying West Boylston Street to replace the grade crossing at Barbers.

[23]: 3 In January 1941, the Massachusetts Department of Public Utilities (DPU) approved the conversion of all remaining streetcar routes to buses.

[23]: 9 [346] Rationing of rubber tires and gasoline began after the United States entered World War II in December 1941.

[23]: 9  Ridership increased during the war years, with over 50 million annual passengers, temporarily returning the Worcester Street Railway to profitability.

The final trip – an inbound car from the Leicester Line cutback of route 19 – arrived in the early morning hours of December 31.

Instead, it purchased enough older buses from United Electric Railways of Providence, Rhode Island to reach the required number.

[26]: 9 [23]: 12, 14 By 1948, the Worcester Street Railway carried 38 million annual passengers (110,000 daily riders) over 222 route miles with 237 buses.

[353][354] In March 1952, the company cut off-peak service on 22 of its 33 routes, claiming that "people are not going out nights, Sundays or holidays because of television.

[363][364] That month, the city began studying whether to set up a public transit authority to replace the private system – a plan supported by both the company and the union.

[372][373] The company received a one-year, $300,000 state subsidy (equivalent to $1.9 million in 2023) as part of legislation in November 1973 that also established regional transit authorities.

[376] The 1974-formed Worcester Regional Transit Authority (WRTA) began subsidizing bus service in the mid-1970s and purchased the company's assets in 1978.