who renamed it the Städtische Strassenbahn Zürich (StStZ). The following year, the horse trams of the ZStG were acquired. Further tramway companies were founded, some operating entirely within the city, some connecting the city with its nearer suburbs, and some running in rural areas entirely beyond the city, but still linked by connections with other lines to the city. Like the EStZ, all these lines were electrified and were built to the metre gauge. The StStZ gradually took over those companies that had significant city operations, usually closing any cross-boundary lines, whilst leaving those lines entirely beyond the city to their own devices. Many companies The many companies that operated trams in and around Zürich are summarised in the table below. Names of companies whose lines were entirely outside the current city boundaries are shown in italic type, and those which still operate tram or other light rail services are shown in bold type. Heyday of the StStZ By the mid-1930s, the StStZ had acquired all the companies that had operated tramways within the city boundaries, with the single exception of the Dolderbahn, which had closed its short tramway in 1930. The standard gauge horse tram lines had all been converted to metre gauge and electrified. The StStZ had also built many tram extensions, resulting in a dense network of tramlines serving most city neighbourhoods. However, in 1927, the StStZ had introduced its first motor bus route, and this was to be followed in 1939 by the first of the city's trolleybus routes. Initially these modes complemented the trams, but at various times they have threatened to replace parts of the tram system, and sometimes succeeded in doing so. In 1940, the StStZ started a modernisation of its trams, introducing the first prototypes of the . Despite Switzerland's neutrality, the economic effects of the second world war slowed down the program, but by 1953 the VBZ, as the StStZ had become in 1950, had taken delivery of 177 such trams. Lines closed While the tram network within the city of Zürich has seen relatively few line closures, the same cannot be said for the lines beyond the city. The StStZ routinely closed any out-of-city lines belonging to the companies it took over. In other cases, private sector operated lines succumbed without StStZ involvement. Out of town closures included: The Schlieren to Dietikon and Schlieren to Weinigen lines of the LSB