Well, that was true for the USA, too, what's more, the Central European network wasn't connected to the British network until the Eurotunnel -- but was connected to the French and Dutch when they still had non-GMT-plus-whole-hour times -- yet still adopted it. And the very first national time, that of New Zealand from 2 November 1868, was GMT+11h30m.

But, I googled around a bit more, and found this:

On January 1, 1879 a standard time zone was introduced for the entire of Sweden. Swedish standard time was set accordingly to the meridian half way between Stockholm on the east coast and Göteborg on the west coast.

Göteborg is 11°58', Stockholm 18°04', that would be rather neatly 15°01', within 4 seconds off CET. So either my three-decades-old West German railway history book erred in the date, or a few seconds difference was eliminated in 1888, or my book still erred and Wiki is right, e.g. the few seconds difference would have been eliminated in 1900...

Now it really bugs me, did Sweden pre-empt even the US or did it conform with GMT+1 only after Central Europe... Could you Google the dates and the subject in Swedish?

I also found that Italian railways began to introduce a national time (Rome Time) from 12 December 1866, but it wasn't official (for example Venice public clocks switched only in 1880); and they joined MEZ/CET on 10 August 1893.

_{*Lunatic*, n.
One whose delusions are out of fashion.}