Mechanical Signals and Boards

Haltetafel und alleinstehende Vorsignaltafel  A standalone Ne 2 board (i.e. a distant signal post plate). The H-board instructs a halting train to stop here. This picture was taken at Hamburg-Dammtor track 1 (S-Bahn), and since the signals are placed to the left of the track, they are meant for wrong track operation. Should in a rare event a train be required to use the left line towards Hamburg Hbf, there is no colour light signal, but the standalone distant signal post plate tells the driver that he is approaching a main signal which may show stop and hence drive at appropriate speed.
Gleissperrensignal (Vorderseite)  The signal device of a derailer, showing aspect Sh 0 (a line-close signal).

The standard position for this derailer is "derailer on, line closed" as you can see by the black part of the operating lever facing down (standard position is black downwards: "dirt facing dirt").

Gleissperrensignal (Rückseite)  The rear of the same signal.
Sh 0: keine Weiterfahrt...  One could suspect that driving beyond is not advisable, but to make sure DBAG puts an Sh 0: stop-no passing signal onto every buffer.
Gsp 0: keine Weiterfahrt  An Sh 0 marks the end of track in Rostock Hbf.
Sh 2 an einem Einfahrstumpfgleis  At dead entry routes instead of an Sh 0 an Sh 2 board is placed. This is a track at Hamburg-Altona.
Weichensignal  This is a point signal for a manually operated point. The point is currently set to straight and for the curved track the box would turn about 90° clockwise. As the black part of the lever weight is facing downwards, this points are set to their standard position.

See also light points signal.

Ankündigungsbake  So 17 Ankündigungsbake (Announcement board) for So 18 signal.
Signal für Rückfallweiche  So 18 signal for spring-loaded points displaying aspect So 18a: Points can be travelled facing points

To the left you see a Wn points signal. Usually black, this one is yellow to indicate print-loaded points

DKW: rechts nach rechts  A signal for double-slip points. The yellow lever weight tells us that there is no "default" position.
Geschwindigkeitsbegrenzung 200 km/h  A DB Lf 7: From here on, the maximum speed is 200 km/h.
Note that this is a special case: Usually, only the begin of a speed restriction is signalled, so you are unlikely to see a 200 km/h signal.
This one is on the Augsburg-Donauwörth line which is equipped with the experimental Sk signalling system (see there). One of its properties is that every speed change is signalled: this sign here is really an end of speed limit - resume 200 km/h line speed signal.
Geschwindigkeitsbegrenzung 50 km/h erwarten  A DR Lf 4 (permanent speed restriction warning board) giving advance notice of a speed restriction of 50 km/h.
Baustelle, 70 km/h erwarten  Lf 1: Expect a temporary speed restriction (in this case: 70 km/h)
DR-Wartezeichen  A DR Ra 11a waiting sign (DB: Ra 11) with a Kreisscheibe at Rostock Hbf. The number plate 4II tells us that for waiting signs the same numbering scheme as for line-close signals is used.
Gleissperre  Another Gleissperre (derailer), the signal (the two white dots) is seen from the rear. The box with the black and yellow stripes is the rear of an electric Sh 0/1 line-close signal.
Weichensignal  A Weichensignal (point signal) showing deflection to the left. Click the picture for a larger version. The yellow-black colouring of the lever weight tells us that this is a Rückfallweiche (spring-loaded point, lit. "fall-back point") which can be trailed in either direction, and that the black part of the weight is facing ground ("dirt facing dirt") means that this point is in its default position.

Usually the point signal should also have a yellow background to indicate that this is a spring-loaded point, but it seems here you should read the point label: Rückfallweiche 2.
Weichensignal einer Rückfallweiche  Another point signal of a spring-loaded point. In DR area, for spring-loaded points also the point signals are coloured yellow.