Source LdenLnight Lday Levening LAeq,16hr LAeq,6hr LAeq,18hr Major Railway Those which have more than 30,000 train passages per year (for mapping rounds other than Round 1)The day-evening-night level indicator for overall annoyance, based upon annual average A-weighted long-term sound over 24 hours. It includes a 5 dB(A) penalty for evening noise (19:00-23:00) and a 10 dB(A) penalty for night-time noise (23:00-07:00)The night level indicator for sleep disturbance, based upon the A-weighted, Leq (equivalent sound level) determined over all the 8-hour night periods (23:00-07:00) of a yearThe day level, the A-weighted, Leq (equivalent sound level), determined over all the 12-hour day periods (07:00-19:00) of a yearThe evening level, the A-weighted, Leq (equivalent sound level) determined over all the 4-hour evening periods (19:00-23:00) of a yearThe equivalent continuous sound level in dB(A) that, over the period 07:00-23:00 hours, contains the same sound energy as the actual fluctuating sound that occurred in that periodThe night level, the A-weighted, Leq (equivalent sound level) determined over all the 6-hour night periods (00:00-06:00) of a yearThe equivalent continuous sound level in dB(A) that, over the period 06:00-24:00 hours, contains the same sound energy as the actual fluctuating sound that occurred in that period The Common Noise Assessment Methods in Europe (CNOSSOS) methodology introduced a significant number of new data requirements and approaches to computing noise emissions to improve the quality of the maps. Thus round 4 noise mapping results should not be compared to previous rounds