DB Class 420

420
Power type	Electric
Builder	MAN, WMD, LHB, MBB, O&K, DUEWAG, WU
Build date	1971
Total produced	480 units
AAR wheel arr.	Bo'Bo'+Bo'Bo'+Bo'Bo'
UIC classification	420/421
Gauge	1,435 mm (4 ft 8 1⁄2 in)
Bogies	2.5 m (8 ft 2 in)
Wheel diameter	0.85 m (33 in)
Length	67.4 m (221 ft 2 in) (23.3 m + 20.8 m + 23.3 m)
Width	3.08 m (10 ft 1 in)
Axle load	15 to 24 t (33,000 to 53,000 lb) depending on series
Locomotive weight	129 to 138 t (280,000 to 300,000 lb) depending on series
Top speed	120 km/h (reachable within 40 s)
Tractive effort	12 x 200 = 2400 kW
Train brakes	−0.9 m/s2 (−3.0 ft/s2) regular, −0.95 m/s2 (−3.1 ft/s2) at emergency stop

The Baureihe 420 is a light-weight commuter electric multiple unit developed for the S-Bahn networks in Germany and was originally commissioned by the Deutsche Bundesbahn for the Munich, Stuttgart and Frankfurt networks. It could seat 194 second class, 17 or 33 first class, depending on series. The pivot distance was 16.5 m (54 ft) in cab cars and 14 m (46 ft) in trailer, with a floor capacity of ca. 1 m. It ran at 15 kV, 16⅔ Hz, with a tractive effort speed of 72 km/h (20 m/s; 45 mph) and acceleration of 0.9 m/s² (3.0 ft/s² or 2.0 mi/(h·s)).

History

It was built from 1971 onwards in several series, later changing the construction from steel to aluminium, making the cars more lightweight and able to carry a greater payload.

It has largely been replaced in said cities by its successor, the Class 423, but some units have been shipped to Stockholm and some have been transferred to the Rhine-Ruhr S-Bahn network. In Sweden the fifteen units received designation X420 serving on the Stockholm commuter rail, and were in service from 2001 until the arrival of the new X60-series in 2006-08.

Today's service

Class 420 unit in Frankfurt am Main

Additionally, in the Rhine-Main Area, many units of class 420 are still in use, especially on lines S8 and S9 of the S-Bahn Rhein Main. Today all trains of this class have been repainted in the DB-typical "traffic red" (verkehrsrot).

Unit 420 001 will be preserved at the DB Museum in Nuremberg. Two 420/421 units in Stuttgart were rebuilt by the ET 420 Plus project, adding air conditioning and passenger information displays to the trains among other things. The aim of this project was to demonstrate a less expensive alternative to new trains in order of keeping the S-Bahn fleet up to date. However, as the new long-term carrier contract with Stuttgart Region includes the acquisition of 83 new class 430 EMU's, all 420's will be withdrawn from service in Stuttgart by 2013.