The first official train through the tunnel was the Silver Fern railcar RM 3 which departed Hamilton railway station for Tauranga on 12 September 1978.
Onboard were various railway officials and a party of 50 disabled Waikato school children.

After a lunch stop at Matamata, Prime Minister Robert Muldoon greeted the assembled crowd and boarded the train.
The next stop was Hemopo, where a crowd had assembled.
They were addressed by Piako County Council Chairman Mr. Thomas, the MP for Piako Mr. Jack Luxton and the Minister of Railways the Hon.
Colin McLachlan.
Then the Prime Minister gave a speech and unveiled a plaque paying tribute to the four workers who had lost their lives.
Finally, he cut a ribbon and declared the tunnel to be open.
The train proceeded to Tauranga with the official party and minus the school children where several civic functions were held.

The project ended up running eight years over time, and over budget.
The final cost was $43 million for the tunnel and $13 million for the deviation, a total of $56 million.
The first official train through the tunnel was the Silver Fern railcar RM 3 which departed Hamilton railway station for Tauranga on 12 September 1978. Onboard were various railway officials and a party of 50 disabled Waikato school children.
After a lunch stop at Matamata, Prime Minister Robert Muldoon greeted the assembled crowd and boarded the train. The next stop was Hemopo, where a crowd had assembled. They were addressed by Piako County Council Chairman Mr. Thomas, the MP for Piako Mr. Jack Luxton and the Minister of Railways the Hon. Colin McLachlan. Then the Prime Minister gave a speech and unveiled a plaque paying tribute to the four workers who had lost their lives. Finally, he cut a ribbon and declared the tunnel to be open. The train proceeded to Tauranga with the official party and minus the school children where several civic functions were held.
The project ended up running eight years over time, and over budget. The final cost was $43 million for the tunnel and $13 million for the deviation, a total of $56 million.
Kaimai Tunnel