While traveling by train, you might have seen railway men waving different colours flags at different times. Do you know what they mean? A red flag or a flag of any colour that is waved vigorously means only one thing…. STOP! A yellow flag tells the train driver to proceed with care, while a green, white or blue flag reassures him that it is okay to proceed. A blue flag stuck on the side of a train means that it should not be moved because someone is working on it. A blue flag on a track means that nothing on that track should be moved. At night, the flags are replaced by lights of the same colour
Sports flags, in some form or other have been used in sports for years. They are used by officials to signify to the fans, other players and officials that a rule has been broken. They are also use to communicate drivers during motor sports, and with participants of water sports. Soccer, rugby and football all have flags that are carried by the linesman and referees to signal when a rule has been broken. Other sports where flags are used are car racing, cycling and yachting rowing go –cart racing, and motorcycle racing. Fans of almost all sports wave flags in the stands to indicate support to their team. Many sports teams and organizations have their own flags. The most famous of these is the flag of the Olympic Games.
Flags have been in use since ancient times, and the oldest state flag still in use is that of 
Denmark. It has a white cross on a red background, and this cross was later adopted by other countries like Norway, Sweden, Finland and Iceland.The flag of Denmark is called the Dannenberg which means ‘the cloth of the Danes’ According to Danish legend, the flag fell from the sky on June 15, 1219, to the Danish king Valdemar ll. This makes it the oldest national flag in Europe still in use. The first recorded use of this flag was in the 1300s.
A flag in the air, and the word ‘flag ‘comes from an ancient Saxon word ‘flakken’ which means to fly or float in the air. The word came into use between the 15th to the 16th centuries in various northern European languages. It signified a piece of cloth, bunting, or similar material that displayed the insignia of a community, an armed force, an office, or an individual.
Semaphore is a flag signaling systems. In this system the letters of the alphabet are signaled by waving a pair of hand-held flags in a particular pattern. The flags are usually square. They are red and yellow in colour and divided diagonally with the red portion on top. The flags are held, arms extended, in various positions representing each of the letters of the alphabet. The pattern resembles a clock face divided into eight positions. Numbers are shown by special signals. Semaphore signals were used to exchange messages between other, but could see each other, but could not hear each other. They were used by railways to communicate with train drivers. Semaphore signals have generally given way to color light signals although there are still many places where semaphore signaling is in use.
Maritime flags are that flown at sea. A national flag flown at sea is called an ensign. There are strict rules and regulations for flying these flags.There is also a system for international maritime signal flags that represent numerals and letters of the alphabet. Each flag has a specific meaning when it is flown independently.[custom_search_and_filter]