Index: trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 5299)
+++ trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 5300)
@@ -40,4 +40,5 @@
 import org.openstreetmap.josm.data.validation.tests.OverlappingAreas;
 import org.openstreetmap.josm.data.validation.tests.OverlappingWays;
+import org.openstreetmap.josm.data.validation.tests.PowerLines;
 import org.openstreetmap.josm.data.validation.tests.RelationChecker;
 import org.openstreetmap.josm.data.validation.tests.SelfIntersectingWay;
@@ -106,4 +107,5 @@
         WayConnectedToArea.class, // ID 2301 .. 2399
         NodesDuplicatingWayTags.class, // ID 2401 .. 2499
+        PowerLines.class, // ID 2501 .. 2599
     };
 
Index: trunk/src/org/openstreetmap/josm/data/validation/tests/BuildingInBuilding.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/BuildingInBuilding.java	(revision 5299)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/BuildingInBuilding.java	(revision 5300)
@@ -1,2 +1,3 @@
+// License: GPL. See LICENSE file for details.
 package org.openstreetmap.josm.data.validation.tests;
 
Index: trunk/src/org/openstreetmap/josm/data/validation/tests/PowerLines.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/PowerLines.java	(revision 5300)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/PowerLines.java	(revision 5300)
@@ -0,0 +1,95 @@
+// License: GPL. See LICENSE file for details.
+package org.openstreetmap.josm.data.validation.tests;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.openstreetmap.josm.command.ChangePropertyCommand;
+import org.openstreetmap.josm.command.Command;
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.data.osm.Way;
+import org.openstreetmap.josm.data.validation.Severity;
+import org.openstreetmap.josm.data.validation.Test;
+import org.openstreetmap.josm.data.validation.TestError;
+
+public class PowerLines extends Test {
+    
+    protected static final int POWER_LINES = 2501;
+    
+    protected Map<Way, String> towerPoleTagMap = new HashMap<Way, String>();
+    
+    public PowerLines() {
+        super(tr("Power lines"), tr("Checks for nodes in power lines that do not have a power=tower/pole tag."));
+    }
+    
+    @Override
+    public void visit(Way w) {
+        if (w.isUsable() && isPowerLine(w)) {
+            String fixValue = null;
+            boolean erroneous = false;
+            boolean canFix = false;
+            for (Node n : w.getNodes()) {
+                if (!isPowerTower(n)) {
+                    errors.add(new PowerLineError(n, w));
+                    erroneous = true;
+                } else if (fixValue == null) {
+                    // First tower/pole tag found, remember it
+                    fixValue = n.get("power");
+                    canFix = true;
+                } else if (!fixValue.equals(n.get("power"))) {
+                    // The power line contains both "tower" and "pole" -> cannot fix this error
+                    canFix = false;
+                }
+            }
+            if (erroneous && canFix) {
+                towerPoleTagMap.put(w, fixValue);
+            }
+        }
+    }
+
+    @Override
+    public Command fixError(TestError testError) {
+        if (isFixable(testError)) {
+            return new ChangePropertyCommand(
+                    testError.getPrimitives().iterator().next(), 
+                    "power", towerPoleTagMap.get(((PowerLineError)testError).line));
+        }
+        return null;
+    }
+
+    @Override
+    public boolean isFixable(TestError testError) {
+        return testError instanceof PowerLineError && towerPoleTagMap.containsKey(((PowerLineError)testError).line);
+    }
+    
+    /**
+     * Determines if the specified way denotes a power line.
+     * @param w The way to be tested
+     * @return True if power key is set and equal to line/minor_line
+     */
+    protected static final boolean isPowerLine(Way w) {
+        String v = w.get("power");
+        return v != null && (v.equals("line") || v.equals("minor_line"));
+    }
+
+    /**
+     * Determines if the specified node denotes a power tower/pole.
+     * @param w The node to be tested
+     * @return True if power key is set and equal to tower/pole
+     */
+    protected static final boolean isPowerTower(Node n) {
+        String v = n.get("power");
+        return v != null && (v.equals("tower") || v.equals("pole"));
+    }
+    
+    protected class PowerLineError extends TestError {
+        public final Way line;
+        public PowerLineError(Node n, Way line) {
+            super(PowerLines.this, Severity.WARNING, 
+                    tr("Missing power tower/pole within power line"), POWER_LINES, n);
+            this.line = line;
+        }
+    }
+}