Czech Railways case study proposal

August 1, 2023

Effects of graffiti on Czech Railways trains

“You can hardly ask people who take the train to work to be afraid of what they will catch on the trains, or to feel uncomfortable in the sprayed trains,” said Petr Borecký, the Central Bohemian Region’s councillor for transport.

Cleaning the CityElefant unit will cost approximately 150 thousand crowns. These costs include staff salaries, the cost of the necessary chemicals and their subsequent ecological disposal. For one train, it is about 40 litres of special solvent and about two thousand litres of water.

Every year, ČD cleans the exteriors of 68 CityElefants in the vicinity of the capital city alone, while another 64 have their interiors cleaned. “Some units have been cleaned two, three or even five times,” Most of the time, around 150 square metres have to be cleaned. It means shutting down the train for one to two days,” said Jiří Ješeta, deputy director general of Czech Railways.


Sound Event Detector (SED) installation targets

▶️ Solving the problem with graffiti sprayers.

▶️ Immediate summoning of security forces even in case of preparation for spraying.

▶️ Reduction of train washing costs.

▶️ Analysis of the places where sprayers are most frequent.

Sprayed Czech Railways train | Source: Czech Radio

Problem solving

01 Procedure for solving the orderInitial analysis to understand the problem sites, identifying a site for initial installation.
02 What a concrete solutionInspection of the site selected for POC implementation, evaluation of coverage options, installation and alternative solutions.
03 Reasons for the chosen solutionSelection of technical options for implementing coverage of the site (still does not have to be SED, but it may turn out, for example, that the site is better covered by perimeter protection using video analysis.
04 Solving problemsThis is a proposal for an impact study. Therefore, we do not yet have options for solving the problems in the case study.

Design solutions in time

The location has been mapped. Placement of 10 SED detectors for PoC purposes and installation of the solution.

Conduct a coverage test at the installation sites.

Evaluation of SED detector performance results.

Second phase of deployment. Identification of additional locations for the deployment of SED detectors.

Installation of SED detectors.

Evaluation of the performance of SED detectors.

Coverage study

Coverage design procedure

  • ONJ Prague (Prague South, railway station).
  • Depot selected on the basis of ČD requirements.
  • Depot coverage was implemented without additional information, experience and “inside” information about the potential for intrusion.
  • Full coverage can be realized from about 20 pieces of equipment, to cover all “deaf” spots it can be assumed up to 50 pieces
  • On the other hand, with additional information, e.g. on the potential for intrusion, it is possible to target these locations and thus reduce the numbers significantly.

Map of coverage

  • Location of SED detectors: in Prague South (ONJ station).
  • Detection coverage range of SED detectors.

Cost of the case study

  • Estimated cost of PoC installation: 10 SED devices = 250 000 CZK excluding VAT + cost of installation on the poles with lighting (approx. 10 – 20 min. work to install the SED).
  • Assumption of the final amount (points of interest at ONJ Prague): between CZK 500,000 and CZK 1,000,000 excluding VAT.

The amounts mentioned above are indicative only.

Results of the case study

This is still a draft case study, so we do not provide concrete results of the project.

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