diff --git a/src/edu/kit/informatik/model/RollingStock.java b/src/edu/kit/informatik/model/RollingStock.java
index 6d08e3b..783448e 100644
--- a/src/edu/kit/informatik/model/RollingStock.java
+++ b/src/edu/kit/informatik/model/RollingStock.java
@@ -27,13 +27,16 @@ public abstract class RollingStock {
      * @param length length of this rolling stock
      * @param couplingFront whether this rolling stock should have a front coupling
      * @param couplingBack whether this rolling stock should have a back coupling
-     * @throws InvalidInputException on invalid user input (zero-sized coach)
+     * @throws InvalidInputException on invalid user input (e.g. zero-sized coach)
      */
     protected RollingStock(final int length, final boolean couplingFront, final boolean couplingBack)
             throws InvalidInputException {
         if (length < 1) {
             throw new InvalidInputException("rolling stock length has to be positive");
         }
+        if (!couplingFront && !couplingBack) {
+            throw new InvalidInputException("rolling stocks needs at least one coupling");
+        }
         this.length = length;
         this.couplingFront = couplingFront;
         this.couplingBack = couplingBack;