Track gauge in Ireland.

Ireland. Cut off from Great Britain and continental Europe by the sea, it might as well be on another planet as far as railways are concerned, and that's because Ireland uses a different track gauge. Back in the 1800s when the railways were first being built, a number of different gauges were in use in Ireland. The Dublin & Kingstown Railway used the same standard gauge of 4' 8 1/2" as most of Great Britain (not counting Brunel's Great Western, but that's another story). Meanwhile the Ulster Railway used a broad gauge of 6' 2" and the as yet unbuilt Dublin & Drogheda proposed a gauge of 5' 2". This was a mess, so the, the board of trade decided in 1846 that Ireland should standardise on one gauge. Bizzarely the gauge of 5' 3" was selected as a compromise between the two gauges in use at the time. This seems wasteful, since rather than regauging the non-complying half half of the island's railways (if they had chosen one of the gauges in use), they would have to change them all!
The use of broad gauge would be fine so long as Ireland's railways remained separate from British railways. However, this might cause a problem if proposals for a bridge over the north channel came to fruition. That would mean there would be a break of gauge in Ulster, resulting in need for transshipment. Frankly, though, due to the depth of the north channel, such a bridge is probably nothing more than a fantasy. The biggest real life problem in today's globalised rolling stock market is producing rolling stock just for Ireland. If stock is transferred from Great Britain, as has been done on occasion, bogies need to be changed to suit the Irish track gauge and vice versa. This is of course an expensive undertaking. A recent rumour appeared in the Railway Magazine that ex-Transpennine Express class 185s could be transferred to Ireland. This might be cheaper than buying in new trains specially made for Ireland, but it would be so much cheaper if they didn't have to be modified. one wonders, if Ireland had used standard gauge, not only would they have had less track to reguage (only the Ulster Railway would have needed regauging; the Dublin & Kingstown would have stayed as it was and the Dublin & Drogheda would have been built to 4' 8 1/2" from new) but stock could have been bought "off the shelf" or even second hand from Great Britain, without modification. Alternately, Irish stock could be exported to Britain, opening up potential for Irish manufacturing and providing a second-hand market for Irish trains.