Light at the end of the tunnel

In this case, the Scotland Street playground from the short tunnel under Rodney Street on the edge of Edinburgh's New Town. Went down to the Lady Haig Poppy Factory on Logie Green Road for a press photocall and took this on the way back. This stretch of tunnel was re-opened for cyclists and pedestrians in 2009, but was originally built in the mid nineteenth century.

In 1836 the Edinburgh Leith and Newhaven Railway Act received Royal Assent to allow for a line to be built from the centre of Edinburgh to Trinity on the Firth of Forth. However its construction was beset by problems and was delayed for several years because of financial difficulties. Sound familiar? Anyway, the Edinburgh, Leith and Newhaven Railway Company opened their horse drawn railway in 1842, providing a direct link from Canonmills to Newhaven Station, just west of Leith. Canonmills Station was later renamed Scotland Street and a new station called Trinity replaced the former Newhaven station.
The line was extended westwards to Granton Harbour in 1846 and a branch was built to the docks at the Port of Leith. In 1847 the line was extended to allow services to operate right into the heart of the city. This involved two tunnels heading southwards. This much shorter tunnel on the north side of Canonmills took the line under Rodney Street and Broughton Road while a much more substantial tunnel went from Canonmills under Scotland Street, Dublin Street and St Andrew Square to a new terminus at Canal Street immediately to the north of North Bridge (later Waverley) station and at right angles to it.
The longer tunnel was 1000yds in length, 24ft in width, and 24ft in height with a gradient of 1-in-27 towards the north.  The roof of the tunnel is just below street level at Scotland Street, but is 49 feet deep at St. Andrew Street and 37 feet deep under Princes Street.  In order to cope with the steep gradient, cable haulage was required, with a stationary winding engine at Canal Street.  Passenger carriages proceeding downhill were steadied by brake trucks, while those heading uphill were hauled by an endless rope, which ran under rollers beneath the rails and was powered by the engine at Canal St. Station.
Robert Louis Stephenson wrote of this tunnel, "The tunnel to the Scotland Street Station, the sight of the trains shooting out of its dark maw with the two guards upon the brake, the thought of its length and the many ponderous edifices and open thoroughfares above, were certainly of paramount impressiveness to a young mind.
It was a subterranean passage, although of a larger bore than we were accustomed to in Ainsworth's novels and these two words, 'subterranean passage,' were in themselves an irresistible attraction and seemed to bring us nearer in spirit to the heroes we loved and the black rascals we secretly aspired to imitate."
In 1862 the line was absorbed into the North British Railway who built a new line to Abbeyhill and Trinity allowing trains from Trinity to be diverted into Edinburgh Waverley from 1868 when both Scotland Street and Princes Street closed to passengers. Scotland Street remained in use as a goods and coal depot, accessed only from the north.

Abridged from Subterranea Britannica

Wouldn't it be amazing to reopen that longer tunnel? Unlikely, given the fact that it cost several hundred thousand pounds to reopen the shorter one that is little more than a long bridge!