Belfast and County Down Railway

The company was incorporated by the Belfast and County Down Railway Act 1846 (9 & 10 Vict. c. lxxxvii) on 26 June 1846 with the first section of line from Belfast to Holywood opening for traffic on 2 August 1848. The line was further extended to Bangor by the Belfast, Holywood and Bangor Railway (BHBR), opening on 1 May 1865, and acquired by the BCDR under the Belfast and County Down Railway (Bangor Transfer) Act 1884 (47 & 48 Vict. c. cxx). The line to Downpatrick was opened on 25 March 1859. The line from Downpatrick to Newcastle was built by the Downpatrick, Dundrum and Newcastle Railway, opening on 25 March 1869 and absorbed by BCDR under the Belfast and County Down Railway (Newcastle Transfer) Act 1881 (44 & 45 Vict. c. ccxiii). The railway's first chief engineer was Sir John Macneill, who was responsible for allowing the railway to cross the marshy River Quoile.

A branch to Ballynahinch was opened in 1858 via Ballynahinch Junction.

A branch line from Downpatrick to Ardglass was opened in 1892, as was a loop line at Downpatrick. This resulted in a 'triangle'-shaped track layout just outside of Downpatrick, allowing trains between Belfast and Newcastle to collect and drop off passengers at the Loop Platform, who would be ferried between there and the main station at Downpatrick by a local train. Thanks to the triangular layout, trains were still capable of operating directly from the main Downpatrick station to Belfast or Newcastle. The branch from Newcastle to Castlewellan was opened on 24 March 1906.

By 1948 the company had 29 locomotives. Two steam railcars from Kitson & Company were acquired in 1905. The locomotive works were at Belfast Queen's Quay railway station and closed in 1950. New carriage works had been opened in 1886, with the last carriage being built in 1923.

Incidents and accidents

In the Ballymacarrett rail crash of 1871, on 13 May, 2 died and 55 were injured when a passenger train ran into a derailed goods train at Ballymacarrett Junction. The goods train derailed when a drunken fireman drove the train into an unfinished turnout, fouling the line.

In the Ballymacarrett rail crash, on 10 January 1945, 22 passengers died and 27 were injured when a railmotor car ran into the rear of a conventional train stopped at a signal at Ballymacarrett Junction. The 7.40 a.m. rail motor Holywood to Belfast crashed into the rear of the 7.10 a.m. Bangor to Belfast train. The darkness and local fog were a factor but the driver of the rail motor was held to blame. The Railway had to pay out some £80,000 in compensation, which crippled the company financially, leading to its early nationalisation in 1948.