[Symbiote]

> still continuing with only 12.7 miles in operation

No, 23.7 miles are in operation. 12.7 miles is the amount that opened in the first stage in 2002.

Washington DC has a population greater than the whole of Denmark, and the DC metro was opened decades ago, so I don't think it's a useful comparison.

[Retric]

How are you getting those numbers? The original line M1 is 13.9 km. The total length of all lines adds up to 20.4 km counting the shared 7.7km section used by M1, and M2 once.

“The metro consists of four lines, M1, M2, M3 and M4. M1 and M2 share a common 7.69-kilometre (4.78 mi) section from Vanløse to Christianshavn,[3] where they split along two lines: M1 follows the Ørestad Line to Vestamager, while M2 follows the Østamager Line to the airport. The metro consists of a total route length of 20.4 km (12.7 mi),[3] and 22 stations, 9 of which are on the section shared by both lines.” https://en.wikipedia.org/wiki/Copenhagen_Metro

Also, the DC metro area is much larger than the area served by the metro system which is why the keep expanding it. In terms of actual daily riders the systems are surprisingly close, though DC gets swamped occasionally for things like Obama’s inauguration etc.

[Symbiote]

I read the first line of the second paragraph ("The original 20.4-kilometre (12.7 mi) system opened in October 2002") and the "System length: 38.2km (23.7mi)" bit from the infobox.

The paragraph you quoted mixes up the situation from before M3/M4 opened with the situation after. I also see where you have taken 13.9km for M1, but on M1's own article page it says 14.3km. Danish Wikipedia gives different figures again.

M1's total length is around 14km, M3 is 15.5km. Christianshavn to the airport is 7km by road, Østerport to Orientkaj about 3km, so the total is roughly 40km.

57 million annual riders on the Washington Metro doesn't seem so much for such a large city. There must be a good chance of getting a seat :-)

Copenhagen's metro claims 107 million annual riders, but the older and more extensive S-train also has 116 million annual riders. Supposedly the total comes to 183 million riders of either/both annually.

[Retric]

Got it, that paragraph is talking about just the M1 and M2 lines even though it starts by mentioning all 4.