# The Use of Earth Observation Data for Railway Infrastructure Monitoring--A Review
## 3 EO-Based Railway Infrastructure Monitoring: Literature Review
### Comparative Analysis of EO Data Use in Railway Infrastructure Monitoring
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Paper** & **Application** & \begin{tabular}{c} **Used** \\ **Satellite Data** \\ **SAR/Optical (O)** \\ \end{tabular} & \begin{tabular}{c} **Used** \\ **Satellite** \\ **Satellite** \\ \end{tabular} & \
\begin{tabular}{c} **Evaluation/Validation Tests** \\ **Evaluation (E)/Testing (T)/** \\ **Validation (V)** \\ \end{tabular} &
\begin{tabular}{c} **Comments** \\ \end{tabular} \\ \hline
[16] & WL & O & PlanetScope Dove & E &
\begin{tabular}{c} Railway line between the cities of \\ Ottawa and Brockville, ON, \\ Canada \\ \end{tabular} \\ \hline
[20] & GD & SAR & Sentinel-1 & E and T &
\begin{tabular}{c} Railway line passing through \\ Provadia town, Bulgaria \\ \end{tabular} \\ \hline
[21] & GD & SAR & TerraSAR-X & E, T, and V &
\begin{tabular}{c} Approximately 50 km of railway \\ tracks of the Swiss Federal \\ Railways network in Northern \\ Switzerland \\ \end{tabular} \\ \hline
[22] & TD & SAR & TerraSAR-X & E, T, and V &
\begin{tabular}{c} Part of the \\ (double-track freight railway) \\ close to Rotterdam, the \\ Netherlands \\ \end{tabular} \\ \hline
[26] & TD & SAR & Radarast-2 & E &
\begin{tabular}{c} Entire railway network of the \\ Netherlands \\ \end{tabular} \\ \hline
[27] & TD & SAR & Sentinel-1 & E and T &
\begin{tabular}{c} Bethve freight train track, the \\ Netherlands \\ \end{tabular} \\ \hline
[38] & GD & SAR & \
\begin{tabular}{c} ENVISAT/ASAR, \\ TerraSAR-X \\ \end{tabular} & E and T &
\begin{tabular}{c} Beijing-Taniph High-Speed \\ Railway, China \\ \end{tabular} \\ \hline
[19] & B & SAR & \
\begin{tabular}{c} Radarsat-2/ \\ Sentinel-1 \\ \end{tabular} & E, T, andV &
\begin{tabular}{c} Bridges that link the cities of \\ Montreal and Longueuil and the \\ cities of Montreal and \\ Saint-Lambert, QC, Canada \\ \end{tabular} \\ \hline
[39] & VG & O & QuickBird & E and T &
\begin{tabular}{c} Railway area in the Southeast of \\ Berlin, Germany \\ \end{tabular} \\ \hline
[40] & TD & SAR & Radarast-2 & E &
\begin{tabular}{c} Zaltbommel, the Netherlands \\ \end{tabular} \\ \hline
[41] & GD & SAR & \
\begin{tabular}{c} ENVISAT/ALOS \\ SAR missions \\ \end{tabular} & E &
\begin{tabular}{c} Castejón-Zaragoza conventional \\ railway line, Spain \\ \end{tabular} \\ \hline
[42] & GD & O & SPOT & E &
\begin{tabular}{c} Oiya city, Nagaoka city, \\ Kawaguchi town, Horinouchi \\ town, and Yamakoshi village, \\ Japan \\ \end{tabular} \\ \hline
[43] & TD & SAR & TerraSAR-X & E, T, and V & South Korea \\ \hline
[34] & VG & O & \
\begin{tabular}{c} Sentinel-2, \\ LANDSAT-7 \\ \end{tabular} & E &
\begin{tabular}{c} Liberec Region, Czech Republic \\ \end{tabular} \\ \hline
[35] & VG & O & Pleiades & E and T &
\begin{tabular}{c} Different railway lines in France \\ \end{tabular} \\ \hline
[44] & GD & SAR & \
\begin{tabular}{c} RADARSAT-1, ESA \\ ERS-1, ESA ERS-2 \\ \end{tabular} & E and T &
\begin{tabular}{c} The Cassia–Monte Mario tunnel \\ in Rome, the \\ High-Speed/High-Capacity \\ Bologna Node tunnel, the \\ Sciama-Tracocai tunnel, the \\ preliminary design of the new \\ Venice–Trieste railway line, Italy \\ \end{tabular} \\ \hline
[45] & GD & SAR & Cosmo-SkyMed & E and T &
\begin{tabular}{c} Several railways in Lombardia \\ region, in the proximity of Milamo \\ city and between Lecco and Como \\ cities, Northern Italy \\ \end{tabular} \\ \hline
[46] & \
\begin{tabular}{c} GD \\ B \\ \end{tabular} & SAR & ENVISAT/ASAR & E &
\begin{tabular}{c} Beiluhe test site of the \\ Qinghai–Tbet railway, China \\ \end{tabular} \\ \hline
[18] & TZ & SAR & TerraSAR-X & E and T & Moerdijk, the Netherlands \\ \hline
[47] & TD & O & Google Maps & E & - \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of papers studying the use of EO data for railway infrastructure monitoring. One of the first reported usages of EO-based railway infrastructure monitoring for track deformation (TD) was reported by [PERSON] et al. [47], who proposed an algorithm for detecting railway tracks using low-quality satellite imagery from Google Maps.