The train to Sandy Row is indeed the Dublin-Belfast Enterprise train, which would have departed and arrived at Belfast Great Victoria Street station when Van wrote the song and when he was a child. It was closed for many years, from the mid-1970s, but is now open again. Great Victoria Street station is very close to Sandy Row.Kennedy then offered this interesting tidbit:
I have always assumed that the line "throwing pennies at the bridges down below" refers to the old custom of throwing a penny out of the railway carriage window whilst crossing the River Boyne at Drogheda and making a wish. It is no longer possible as you can't open the railway carriage windows anymore because the train is air-conditioned.The rail mention in "Cyprus Avenue" is a bit trickier to unravel. It may be another reference to the Dublin-Belfast Enterprise line. There's also the possibility it's an allusion to the Belfast and County Down Railway (BCDR), which ran through Morrison's Bloomfield neighborhood in East Belfast. At its peak, the BCDR covered 80 miles, all within County Down. Desmond Coakham's book on the railway states that during its heyday the BCDR carried the heaviest passenger traffic in Ireland. According to a link Kennedy provided, the station closest to Morrison's home was Bloomfield. However, based on information from that same link, the BCDR's Belfast-Comber-Donaghadee line closed in April of 1950. Morrison turned five that August, so any memories of Bloomfield Station, the BCDR, and the lonesome and pining engine drivers would likely be murky at best. Today, a linear park known as the Comber Greenway follows the path of the former BCDR. It's about a 10-minute walk from Morrison’s former home on Hyndford Street; a portion of it runs between Martinez Avenue and Cyprus Avenue. A pamphlet describing the greenway urges visitors to look for the remains of former railway platforms.