--- a/src/engine.h	Sun May 06 14:59:01 2007 +0000
+++ b/src/engine.h	Sun May 06 15:01:44 2007 +0000
@@ -16,6 +16,12 @@
 	RAILVEH_WAGON,       ///< simple wagon, not motorized
 };
 
+enum EngineClass {
+	EC_STEAM,
+	EC_DIESEL,
+	EC_ELECTRIC,
+};
+
 struct RailVehicleInfo {
 	byte image_index;
 	RailVehicleTypes railveh_type;
@@ -26,7 +32,7 @@
 	uint16 weight;
 	byte running_cost_base;
 	byte running_cost_class;
-	byte engclass;         ///< 0: steam, 1: diesel, 2: electric
+	EngineClass engclass;           ///< Class of engine for this vehicle
 	byte capacity;
 	CargoID cargo_type;
 	byte ai_rank;

--- a/src/newgrf.cpp	Sun May 06 14:59:01 2007 +0000
+++ b/src/newgrf.cpp	Sun May 06 15:01:44 2007 +0000
@@ -447,21 +447,21 @@
 			 */
 			FOR_EACH_OBJECT {
 				uint8 traction = grf_load_byte(&buf);
-				int engclass;
+				EngineClass engclass;
 
 				if (traction <= 0x07) {
-					engclass = 0;
+					engclass = EC_STEAM;
 				} else if (traction <= 0x27) {
-					engclass = 1;
+					engclass = EC_DIESEL;
 				} else if (traction <= 0x31) {
-					engclass = 2;
+					engclass = EC_ELECTRIC;
 				} else if (traction <= 0x41) {
-					engclass = 2;
+					engclass = EC_ELECTRIC;
 				} else {
 					break;
 				}
-				if (rvi[i].railtype == RAILTYPE_RAIL     && engclass == 2) rvi[i].railtype = RAILTYPE_ELECTRIC;
-				if (rvi[i].railtype == RAILTYPE_ELECTRIC && engclass != 2) rvi[i].railtype = RAILTYPE_RAIL;
+				if (rvi[i].railtype == RAILTYPE_RAIL     && engclass == EC_ELECTRIC) rvi[i].railtype = RAILTYPE_ELECTRIC;
+				if (rvi[i].railtype == RAILTYPE_ELECTRIC && engclass != EC_ELECTRIC) rvi[i].railtype = RAILTYPE_RAIL;
 
 				rvi[i].engclass = engclass;
 			}

--- a/src/table/engines.h	Sun May 06 14:59:01 2007 +0000
+++ b/src/table/engines.h	Sun May 06 15:01:44 2007 +0000
@@ -346,7 +346,7 @@
  * @param l railtype
  * Tractive effort coefficient by default is the same as TTDPatch, 0.30*256=76
  */
-#define RVI(a, b, c, d, e, f, g, h, i, j, k, l) { a, b, c, {l}, d, e, f, g, h, h, i, j, k, 0, 0, 0, 0, 76, 0 }
+#define RVI(a, b, c, d, e, f, g, h, i, j, k, l) { a, b, c, {l}, d, e, f, g, h, (EngineClass)h, i, j, k, 0, 0, 0, 0, 76, 0 }
 #define M RAILVEH_MULTIHEAD
 #define W RAILVEH_WAGON
 #define G RAILVEH_SINGLEHEAD

--- a/src/vehicle.cpp	Sun May 06 14:59:01 2007 +0000
+++ b/src/vehicle.cpp	Sun May 06 15:01:44 2007 +0000
@@ -2454,9 +2454,9 @@
 									scheme = LS_PASSENGER_WAGON_STEAM;
 								} else {
 									switch (RailVehInfo(parent_engine_type)->engclass) {
-										case 0: scheme = LS_PASSENGER_WAGON_STEAM; break;
-										case 1: scheme = LS_PASSENGER_WAGON_DIESEL; break;
-										case 2: scheme = LS_PASSENGER_WAGON_ELECTRIC; break;
+										case EC_STEAM:    scheme = LS_PASSENGER_WAGON_STEAM;    break;
+										case EC_DIESEL:   scheme = LS_PASSENGER_WAGON_DIESEL;   break;
+										case EC_ELECTRIC: scheme = LS_PASSENGER_WAGON_ELECTRIC; break;
 									}
 								}
 							} else {
@@ -2466,9 +2466,9 @@
 							bool is_mu = HASBIT(_engine_info[engine_type].misc_flags, EF_RAIL_IS_MU);
 
 							switch (rvi->engclass) {
-								case 0: scheme = LS_STEAM; break;
-								case 1: scheme = is_mu ? LS_DMU : LS_DIESEL; break;
-								case 2: scheme = is_mu ? LS_EMU : LS_ELECTRIC; break;
+								case EC_STEAM:    scheme = LS_STEAM; break;
+								case EC_DIESEL:   scheme = is_mu ? LS_DMU : LS_DIESEL;   break;
+								case EC_ELECTRIC: scheme = is_mu ? LS_EMU : LS_ELECTRIC; break;
 							}
 						}
 						break;