be delivered by mid-2007. However, the last tranche of 13 units arrived in Frankfurt in 2010. The last class 423 railcar (423 456) was delivered at the end of October 2010. Short-term rental vehicles were also used by S-Bahn Stuttgart. The reason for the delay was the photocell problem. Between 2013 and 2016, all of the Frankfurt 423 series railcars were modernized to take them to the level of the successor 430 series, after six years in service. This includes: the replacement of all LCD displays with larger LED displays a modernization of the interior with new seat cushion design the retrofitting of video surveillance cameras An adaptation of the passenger information through the installation of progress monitors and alignment of the announcement system to that of the ET430 (this step has not been completed to date [as of: August 2016]) the refurbishment of the car bodies with new paint the retrofitting of microphone units for wheelchair users as well as the installation of new door closing signals. The last point brought the modernized railcar and the RMV as the initiator of the modernization in the early days of severe criticism, as many passengers and train employees the new door signals (which also include a signal when the doors are open) as annoying, even annoying. The RMV referred to existing EU directives, which oblige the installation of such signals, admitted, however, that there had been a manufacturer-design error in the installation of the new signals, which could have increased the intensity of the beep unintentionally. Class 430 The DB class 430 completely replaced the class 420 in 2014. In normal operation, only the class 423 and 430 are now in service. 91 430 series kits were supplied, which is 29 units more than needed for a mere replacement. The fleet was increased from 162 vehicles to 191 traction units. On 5 May 2014 took place on the S1 (Wiesbaden - Rödermark-Ober-Roden) and the amplifier courses of the S8 between Frankfurt Hbf and Kelsterbach the first passenger service of the class 430 in the Rhine-Main area. Almost three weeks later, on May 23, 2014, the S7 (Frankfurt Hbf - Riedstadt-Goddelau) was completely converted to the 430 series. At the end of October, the operations began on the "long" S8 and S9, since November 3, 2014, these lines have been completely reorganized. The introduction of the new railcars was, as with the