In 1886, he joined the New Zealand Railways Department as an engineering draughtsman, having studied at the Otago School of Mines to qualify for the position.

When Troup became NZR's architect there were 7 standard station designs, dating from 1874, during Vogel's rail making boom.

e.g., Glenhope,[6] Kaikoura,[7] Kawakawa,[8] Ohakune,[9] Otaki,[10] Pukekohe,[11] Rangiora, Te Kuiti[12] and Waihi.

[26] Troup was the 23rd mayor of Wellington, the capital of New Zealand, from 1927 to 1931, after being a councillor from 1925 (the year he retired from the Railways) to 1927; he was a member of the (anti-Labour) Civic League.

He decided not to stand for a third term as mayor in 1930 for health reasons, though with the Depression there was opposition to municipal spending.

[28] Troup stood unsuccessfully for the parliamentary seat of Wellington North as the Reform Party candidate in the 1931 election.

In 1935, he was awarded the King George V Silver Jubilee Medal,[29] and in the 1937 New Year Honours, he was appointed a Knight Bachelor, for public services.