Railroad chronometer

specialized timepiece once used for safe operation of trains

en-US/ˈɹeɪlˌɹoʊd kɹəˈnɑmɪtɚ/
en-GB/ˈɹeɪlɹəʊd kɹəˈnɒmɪtə/

ক্যাটাগরি:

stopwatch