| Alzey–Marnheim | |
| Routenumber: | 661 (2017) |
| Linenumber: | 3322 (Marnheim state border) 3523 (state border–Alzey) |
| Linelength: | 20.5 km |
| Linelength Footnotes: | (Line class: C4 [1]) |
| Gauge: | 1,435 mm |
| Maxincline: | 13.5 ‰ % |
| Minradius: | 300 m |
| Speed: | 100 km/h max. |
The Donnersberg Railway (German: Donnersbergbahn) is a branch line from Alzey to Kirchheimbolanden, which originally ran as far as Marnheim. Although it was once part of the main line from Kaiserslautern to Mainz, the Pfrimm Viaduct was blown up in 1945 during the Second World War between Kirchheimbolanden and Marnheim, disrupting the route. Plans to reinstate the main line with a new route came to nothing. Passenger services ceased on the remaining section of line in 1951, but were reactivated in 1999.
| Pfrimm ViaductFile:Marnheim.jpg | Marnheim station, early 20th centuryFile:Donnersbergbahn 21 9.jpg | The Donnersberg Railway just before Kirchheimbolanden |