## 3 Life-Cycle Costs (LCC)
### Operation and Maintenance Costs  
The operation and maintenance of the project include various costs required to maintain the normal service of the railway tunnel throughout its overall design life after the project construction. Operation costs can be classified into several main parts which are management of operation, traffic monitoring costs, and emergence costs. The maintenance costs primarily cover electrical costs, mechanical costs, and structural costs. Operation costs mainly cover labour and vehicle fees, and traffic monitoring accounts for much of the cost of monitoring systems. Considering the long service life of the monitoring system, the costs of this system are considered to be uniformly distributed over its service life. Vehicles are considered in the same way. The replacement of materials during the maintenance process is assumed to happen every two years. Due to the fact that the design life of the rail (50 years) is less than that of the tunnel (100 years), the rail needs to have major maintenance which 10.97 million USD is assumed when its operation years reach its design life. The basic annual operation and maintenance costs are estimated in Tables 4 and 5, respectively. These basic annual costs are estimated for the first year after project construction. The basic annual operation and maintenance costs are assumed to be the same for each year of operation. The economic design lives of the rail and the tunnel are 50 and 100 years respectively. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Components** & **Costs (Million USD/km)** & **Capital Cost (Million USD)** \\ \hline Civil works (ballast and below) & 8.33 & 23.44 \\ Track (rail and sleeper) & 1.46 & 4.11 \\ Signalling and communications & 0.73 & 2.06 \\ Electrification & 0.88 & 2.47 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Railway cost. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Project** & **Tunnel** & **Year** & **Length (km)** & **Cost** & **Cost (Billion USD)** & **Cost/Length (Million USD/km)** \\ \hline \multirow{3}{*}{\begin{tabular}{c} Turin–Lyon \\ high-speed railway \\ \end{tabular} } & Mont d’Ambin Base & \multirow{3}{*}{2016} & \multirow{3}{*}{57.5} & \multirow{3}{*}{68 billion} & \multirow{3}{*}{9.4} & \multirow{3}{*}{82.02} \\  & Tunnel & & & & \\ \cline{1-1} \cline{5-5}  & \multirow{2}{*}{2016} & \multirow{2}{*}{57.1} & \multirow{2}{*}{6} & \multirow{2}{*}{9.4} & \multirow{2}{*}{82.02} \\ \cline{1-1} \cline{5-5}  & & & & & \\ \hline Kaikyo Line & Seikan Tunnel & 1988 & 53.85 & \
\begin{tabular}{c} \(\forall\)1.1 \\ trillion \\ \end{tabular} & 7 & 129.99 \\ \hline Eurostar & Channel Tunnel & 1994 & 50.45 & \(\
ot\)9 billion & 11.8 & 233.89 \\ \hline \begin{tabular}{c} Suseo high-speed \\ railway \\ \end{tabular} & Yulhyeon Tunnel & 2016 & 50.3 & N/A & 3 & 59.64 \\ \hline \begin{tabular}{c} Chongqing–Lanzhou \\ railway \\ \end{tabular} & West Qinling Tunnel & 2016 & 28.236 & N/A & 11.3 & 400.20 \\ \hline \
\begin{tabular}{c} Jinghu high-speed \\ railway \\ \end{tabular} & Xikema & 2008 & 2.8 &
\begin{tabular}{c} \(\forall\)178.56 \\ million \\ \end{tabular} & 0.025 & 8.93 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Examples of construction cost of railway tunnels. the project, two project discount rates of 1% and 4% are employed for comparison in the following LCC analysis [38]. NPV of the project can be calculated by the following equation. \[NPV=\sum_{t=1}^{n}\frac{R_{t}}{\left(1+i\right)^{t}} \tag{1}\]  
where \(R_{t}\) is the net cash inflow-outflows during a single period, \(t\); \(i\) is the discount rates which are 1% and 4% respectively; \(n\) is the number of timer periods which is the design life of 100 years in this analysis. Since both the construction and operation and maintenance stages are significant, the cost of each stage of the tunnel will be analysed using NPV values. As an accurate discount rate cannot be provided, the effect of the discount rate will also be analysed.