(Germany )HAMBURG-U4

Hamburg
Hamburg public transport is mostly based on U-Bahn (typhical Deutch metro system) and S-Bahn (suburban raiways with high frequencies) networks.
The first U-Bahn section to be opened was Rathaus-Barmbek (part of the current U3 line) in 1912, followed (1915) by Kellinghusenstrasse-Ohlsdorf (part of U1), Schlump-Hellkamp (U2; the last terminal - located between Oster and Lutterothstrasse- was abandoned years later) and Hauptbahnhof-Rothenburgsort (which has been subsequently included in the S-Bahn network). Other sections were added in 1934: Ohlsdorf-Ochsenzoll ("Langenhorner Bahn") and Kellinghusenstrasse-Jungfernstieg ("KellJung-Linie") now both part of the current U1, Barmbek-Grosshansdorf/Ohlstedt ("Walddörferbahn") now included in U2 and U1 tracks. The whole network was heavly damaged during the second world war (Hauptbahnhof-Rothenburgsort section interrupted its operations). The subsequent reconstruction was followed by further extensions of the current U1 (1960: Messberg-Hauptbahnhof; 1962: Hauptbahnhof-Wandsbek Markt; 1963: Wandsbek Markt-Wandsbek Gartenstadt) and U2 (1962: Billstedt-Lutterothstrasse; 1966: Lutterothstrasse-Hagenbecks Tierpark; 1967: Berliner Tor-Horner Rennbahn-Legienstrasse; 1969: Legienstrasse-Billstedt; 1970: Billstedt-Merkenstrasse). The direct connection to the city center was assured by the development of new segments, as Schlump-Berliner Tor section (U3, 1968), Schlump-Gansemarkt (U2, 1970) and Gansemarkt-Jungfernstieg (U2, 1973). Years '80s and '90 s brought the current newtork asset, with new stretches of U2 (1983: Hagenbecks Tierpark-Niendorf Markt, extended up to Niendorf Nord in 1991), U3 (1990: Merkenstrasse-Mummelmannsberg) and U1 (1996: Garstedt-Norderstedt Mitte).
Since 2007 works are going on for the costruction of the fourth line (U4), which has been planned during years '70s; many alternatives were considered during the long period before the beginning of the works for the final solution. U4 track will connect the docks area (HafenCity) to the city center, joining U2 at Jungfernstieg and running parallel U2 up to Billstedter, via Hauptbahnhof and Berliner Tor. Another U3 extension is expected in the next future, consisting in another branch starting from Barmbek (besides the existing Barmbek-WandsBek Gartenstadt section) in order to join Steilshoop and Bramfeld (with a grade separated crossing solution).
Hochbahn (official site)

Country	Germany
Line	U4
Inhabitants	City 1.700.000, District 2.500.000
Date opening	2011
Future development:	--
Length (km)	4.0
Track sections	totally underground (bored tunnel: 2.8 km; cut&cover: 1.2 km)
Stops	11, average distance m 400
Platforms	--
Platform doors	--
general characteristics	length 125 m, width --
n. of vehicles	27
n. of cars per vehicle	12
Type	steel wheels
Vehicle dimensions (m)	length 120 - width 2.61
Vehicle capacity (pax)	672 (288 seated)
Frequency	1'/5'
Current/Voltage	750 V DC (third rail)
Guide/gauge	standard gauge rails (1435 mm)
Speed Km/h	Comm --, Max 80
Accel./Decel. (m/sec2)	--
System capacity	20.000 pphpd
Ridership	35.000 pax/day
Total cost	298 M Euro
Staff	--
System builder	BOMBARDIER-ALSTOM
Model	DT5
NOTE	DT5 rolling stock shared with U3 option for further 40 vehicles