Although the Rhein City's subway was completed a long time ago, it still requires some time before normal operations can begin because the current Rhein City is quite sparse, and there is essentially no need for a subway to alleviate traffic.
This results in the Rhein City's subway being completed earlier than Hungary's subway, but the official usage is much later. In fact, the subway in Rhein City was completed as early as 1896, and as for Ernst's mentioned completion time of the subway beneath the Rhein Palace, it's actually referring to the second line of Rhein City's subway.
After all, it involves the royal palace, so the design of the second line is more complex and the standards are higher. Additionally, the second line's section between the government and Rhein Palace has supporting shelters, temporary command centers, and other facilities, resulting in a larger project.
