TRAINS is a comprehensive database at the most disaggregated level of Harmonized System (HS), covering tariff and non-tariff measures as well as import flows by origin for more than 150 countries. Tariff information contains not only applied MFN tariff rates, but also to the extent possible, various preferential regimes including GSP, RTA and PTA rates as well as many bilateral agreement rates. Imports flow is drawn from UN COMTRADE whenever the flow has been reported therein. However, for a country/year for which imports flow is not reported in COMTRADE, mirror trade is used instead. Non-tariff measures (NTMs) are collected and classified according to the NTM classification system developed for this purpose. A new classification system was introduced in 2009 and the NTM data from that year onward are classified accordingly.