All the tramways in Denmark began as private companies, and in the beginning of the 20th century the companies of Copenhagen were gathering in one company:

and in 1902 the linenumbers were introduced.

Ealier the same year the colored lanterns were introduced so you, even if you were far away, could see which line was coming. The colored lanterns were the basis for the great idea it was to color the linenumbers in the same colors as the lanterns.

In 1902 only 8 lines were running, so it was rather easy to find out how the colors should be. After a few years new lines began to run, and the company, De Københavnske sporveje, had to think about colors in another way.

From line no. 9 to 14 they used 3 colors and line no. 15 and 16 were the last lines with colored shields and lanterns.

The fantasy stopped so the rest of the numbers were all black and white.