Lyttelton Railway Station

Lyttelton Line is a name sometimes used to refer to the section of the Main South Line in New Zealand's South Island between Lyttelton and Christchurch, and can also be used to refer to the operations on this section. As it has always been part of the Main South Line (originally the Canterbury Great Southern Railway), this name has never been officially used to refer to the track itself.
The line between Lyttelton and Christchurch is notable for several reasons, including: incorporating part of the first public railway in New Zealand, between Ferrymead and Christchurch; including in its route the still operational first railway tunnel in New Zealand; and, having been the site of the first electrified suburban service in New Zealand.
Part of the Lyttelton Line was originally operated as New Zealand’s first public railway, connecting the city of Christchurch to a wharf at Ferrymead. Because of the inaccessibility of the harbour at Lyttelton, shipping traffic berthed at the Ferrymead wharf from which people and supplies were transported to Christchurch by train. The construction of such a long and expensive tunnel and line in was controversial in the 1850s and 1860s, see William Moorhouse. Following the opening of the Lyttelton rail tunnel on 9 December 1867, the portion of the line from the main line to the wharf reverted to branch line status, but quickly lost its traffic to the line through to Lyttelton and became a siding after July 1868.
As with other railway lines then under construction by the Canterbury Provincial Council, the line and the tunnel were constructed to accommodate 5 ft 3 in (1,600 mm) rolling stock at the behest of contractors Holmes & Richardson of Melbourne, as this was the gauge they were already working with in Victoria. The line remained this way until, following the abolition of provincial government in New Zealand and the establishment of a new uniform national track gauge, the line was converted to 3 ft 6 in(1,067 mm) by April 1876. Double-tracking of the line was completed as far as Heathcote in 1878. Though NZR considered duplicating the Lyttelton tunnel in 1914, this never went ahead
Ferrymead Railway Station - Holds the record for being "First Station to open and frist station to close"

The first Christchurch railway station on the broad-gauge line that ran to Ferrymead : trains are no. 1 (Pilgrim) & no. 2 locomotives.
[ca. 1864]
The original line was built with the same 5 ft 3 in (1,600 mm) gauge as the Canterbury Provincial Railways to suit rolling stock imported from the Melbourne and Essendon Railway Company in the Australian state of Victoria. It serviced ships which docked at the Ferrymead wharf. Construction of the tunnel to the port of Lyttelton was in progress: when this was finished in 1867, the line to Ferrymead became a branch and thereafter carried little traffic. After 27 July 1868, the line was used as a siding, by which time the station buildings had been relocated to Christchurch and Heathcote station. It was the first railway in New Zealand to be both opened and closed.
The Museum of Science and Industry, as it was then called, began in Christchurch in the early 1960s when a group of like-minded individuals banded together to set up a pilot project at Garvins Road in Hornby. At that time the Canterbury Branch of the NZRLS applied to the New Zealand Railways Department to lease part of the old Southbridge Branch at Prebbleton. When this was turned down, Ferrymead became a serious possibility. The Museum of Science and Industry and the Canterbury Branch decided that the Ferrymead site was ideal. The centenary of the original line was commemorated in 1963 and the beginnings of the present Ferrymead Railway date to November 1964.
Info you need to find GZ
At stage 1 there is the old signal box, you will find a metal plaque by the stairs and this will help you find the final.
A = Number of letters in the 3rd word
B = the number of letters in the 1st word
C = Number of letters in the 4th word
S 43 34 0AB (AB check sum 9)
E172 41 6BC (BC check sum 7)