At its peak, with over 60 miles (97 km) of active line, the system was heavily used, profitable and advanced in technology and passenger facilities, with near-full electrification complete from 1901.

One feature of this law was that each establishment of a tramway operation required approvals including those of the Irish Privy Council, and an act of the Imperial Parliament, onerous and expensive provisions.

c. lxxxviii), setting up the first company to actually deliver service, and the associated similarly named act of 1872, finalising initial routes and other rules.

c. 66), also known as "Balfour's Act", which aimed to encourage tram-like or light rail systems in poorer areas, and increased the potential for government to support such projects.

With more guarantees from local authorities, more light rail systems were developed, with Dublin's extensive network just part of a total of 581 miles (935 km) by 1906.

[4][8] In 1878, the DSDTC was acquired by the Imperial Tramways Company, who in 1893 secured an Act of Parliament allowing them to purchase the BKT, and to use electrical and mechanical power.

[11] Also included as part of the deal, the DUTC agreed not to charge more than one penny from the Pillar to any city boundary less than 1.5 miles (2.4 km) away.

[15] In 1913, the Dublin tram system was central to the Dublin lock-out, when DUTC members walked off the job over the refusal of William Martin Murphy to allow some[17] workers to join the Irish Transport and General Workers' Union[18] The DUTC opened its first bus route in 1925, progressively replacing the trams until the closure of their last route, the No.

According to the then Minister for Justice Seán Mac Eoin, "A force of 60 guards, including 2 superintendents, 1 inspector, 8 sergeants and 3 motor-cyclists[,] were placed on duty over the route," but they were unable to protect the last tram from damage by souvenir hunters.

In 1910, there were seventeen Dublin United Tramways Company (DUTC) routes, each identified with a different symbol (since 1903), and named for their terminus stations.

Route numbers replaced the symbols from 1918, rising from 1 at Ringsend to 30 for Dollymount (and 31 for Howth, shared with another company) in a circuit around the city.

The Dublin region had six other tram companies in the early 20th century, two operating back-to-back lines to Lucan and Leixlip, and two similarly in the direction of Blessington and Poulaphouca.

[30][31] Although the DBST connected with the DUTC system at Terenure, through-running was not allowed, as Dublin Corporation prohibited the operation of steam trams within the city.

Dublin and Wicklow county councils guaranteed this line, Kildare however, despite usage from the direction of Harristown (and Kilcullen and Ballymore Eustace) refused to be involved.

The potential inclusion of the line into the new Great Southern Railways entity was debated in the Dáil in 1924, but the government successfully opposed the idea.

The DBST was closed by the Dublin and Blessington Steam Tramway (Abandonment) Act, 1932, after years of being a burden on ratepayers, especially in the much more sparsely populated Wicklow.

[34] After it went into liquidation, its assets were sold at auction on 1 August 1899, including around 6,160 yards (5,630 m) of rails, two bogie passenger carriages, two other passenger carriages, two goods wagons, a locomotive engine, a water ram in the River Liffey and much other material[35] Lucan and Leixlip Electric Railway A new line was laid close to the original steam line, over a decade later, under an Order in Council, the Lucan and Leixlip Electric Railway Order, 1910, by a completely new company.

[37] The tramway had direct access to the Liffey via a specially constructed quay and made use of a spiral tunnel to overcome a height difference on the brewery site.

The tunnel cost £3,000 and construction spanned 1877–1878[38]The broad gauge tramway connected the brewery with the goods yards of Heuston Station.