--- a/engine.h	Thu Dec 28 11:52:12 2006 +0000
+++ b/engine.h	Thu Dec 28 13:18:07 2006 +0000
@@ -27,6 +27,7 @@
 	                    //       kind of visual effect to generate for a vehicle (default, steam, diesel, electric).
 	                    //       Same goes for the callback result, which atm is only used to check if a wagon is powered.
 	byte shorten_factor; // length on main map for this type is 8 - shorten_factor
+	byte tractive_effort; ///< Tractive effort coefficient
 	byte user_def_data; ///! Property 0x25: "User-defined bit mask" Used only for (very few) NewGRF vehicles
 } RailVehicleInfo;
 

--- a/lang/english.txt	Thu Dec 28 11:52:12 2006 +0000
+++ b/lang/english.txt	Thu Dec 28 13:18:07 2006 +0000
@@ -2604,6 +2604,7 @@
 STR_885C_BROKEN_DOWN                                            :{RED}Broken down
 STR_885D_AGE_RUNNING_COST_YR                                    :{BLACK}Age: {LTBLUE}{STRING2}{BLACK}   Running Cost: {LTBLUE}{CURRENCY}/yr
 STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED                         :{BLACK}Weight: {LTBLUE}{WEIGHT_S}  {BLACK}Power: {LTBLUE}{POWER}{BLACK} Max. speed: {LTBLUE}{VELOCITY}
+STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED_MAX_TE                  :{BLACK}Weight: {LTBLUE}{WEIGHT_S} {BLACK}Power: {LTBLUE}{POWER}{BLACK} Max. speed: {LTBLUE}{VELOCITY} {BLACK}Max. T.E.: {LTBLUE}{FORCE}
 STR_885F_PROFIT_THIS_YEAR_LAST_YEAR                             :{BLACK}Profit this year: {LTBLUE}{CURRENCY}  (last year: {CURRENCY})
 STR_8860_RELIABILITY_BREAKDOWNS                                 :{BLACK}Reliability: {LTBLUE}{COMMA}%  {BLACK}Breakdowns since last service: {LTBLUE}{COMMA}
 STR_8861_STOPPED                                                :{RED}Stopped
@@ -3045,6 +3046,7 @@
 STR_PURCHASE_INFO_REFITTABLE_TO                                 :{BLACK}Refittable to: {GOLD}
 STR_PURCHASE_INFO_ALL_TYPES                                     :All cargo types
 STR_PURCHASE_INFO_ALL_BUT                                       :All but {GOLD}
+STR_PURCHASE_INFO_MAX_TE                                        :{BLACK}Max. Tractive Effort: {GOLD}{FORCE}
 
 ########### String for New Landscape Generator
 

--- a/newgrf.c	Thu Dec 28 11:52:12 2006 +0000
+++ b/newgrf.c	Thu Dec 28 13:18:07 2006 +0000
@@ -416,6 +416,10 @@
 			FOR_EACH_OBJECT ei[i].callbackmask = grf_load_byte(&buf);
 			break;
 
+		case 0x1F: /* Tractive effort coefficient */
+			FOR_EACH_OBJECT rvi[i].tractive_effort = grf_load_byte(&buf);
+			break;
+
 		case 0x21: /* Shorter vehicle */
 			FOR_EACH_OBJECT rvi[i].shorten_factor = grf_load_byte(&buf);
 			break;
@@ -466,7 +470,6 @@
 
 		/* TODO */
 		/* Fall-through for unimplemented one byte long properties. */
-		case 0x1F: /* Tractive effort */
 		case 0x20: /* Air drag */
 		case 0x26: /* Retire vehicle early */
 			/* TODO */
@@ -3692,3 +3695,4 @@
 	CalculateRefitMasks();
 }
 
+

--- a/table/engines.h	Thu Dec 28 11:52:12 2006 +0000
+++ b/table/engines.h	Thu Dec 28 13:18:07 2006 +0000
@@ -341,8 +341,9 @@
  * @param i capacity
  * @param j cargo_type
  * @param k ai_rank
+ * 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) { a, b, c, d, e, f, g, h, h, i, j, k, 0, 0, 0, 0, 0 }
+#define RVI(a, b, c, d, e, f, g, h, i, j, k) { a, b, c, d, e, f, g, h, h, i, j, k, 0, 0, 0, 0, 76, 0 }
 #define M RVI_MULTIHEAD
 #define W RVI_WAGON
 #define S 0

--- a/train_cmd.c	Thu Dec 28 11:52:12 2006 +0000
+++ b/train_cmd.c	Thu Dec 28 13:18:07 2006 +0000
@@ -55,6 +55,54 @@
 
 
 /**
+ * Recalculates the cached total power of a train. Should be called when the consist is changed
+ * @param v First vehicle of the consist.
+ */
+void TrainPowerChanged(Vehicle* v)
+{
+	Vehicle* u;
+	uint32 power = 0;
+	uint32 max_te = 0;
+
+	for (u = v; u != NULL; u = u->next) {
+		const RailVehicleInfo *rvi_u;
+		bool engine_has_power = true;
+		bool wagon_has_power = true;
+
+		/* Power is not added for articulated parts */
+		if (IsArticulatedPart(u)) continue;
+
+		if (IsLevelCrossingTile(u->tile)) {
+			if (!HasPowerOnRail(u->u.rail.railtype, GetRailTypeCrossing(u->tile))) engine_has_power = false;
+			if (!HasPowerOnRail(v->u.rail.railtype, GetRailTypeCrossing(u->tile))) wagon_has_power = false;
+		} else {
+			if (!HasPowerOnRail(u->u.rail.railtype, GetRailType(u->tile))) engine_has_power = false;
+			if (!HasPowerOnRail(v->u.rail.railtype, GetRailType(u->tile))) wagon_has_power = false;
+		}
+
+		rvi_u = RailVehInfo(u->engine_type);
+
+		if (engine_has_power && rvi_u->power != 0) {
+			power += rvi_u->power;
+			/* Tractive effort in (tonnes * 1000 * 10 =) N */
+			max_te += (u->u.rail.cached_veh_weight * 10000 * rvi_u->tractive_effort) / 256;
+		}
+
+		if (HASBIT(u->u.rail.flags, VRF_POWEREDWAGON) && (wagon_has_power)) {
+			power += RailVehInfo(u->u.rail.first_engine)->pow_wag_power;
+		}
+	}
+
+	if (v->u.rail.cached_power != power || v->u.rail.cached_max_te != max_te) {
+		v->u.rail.cached_power = power;
+		v->u.rail.cached_max_te = max_te;
+		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
+		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
+	}
+}
+
+
+/**
  * Recalculates the cached weight of a train and its vehicles. Should be called each time the cargo on
  * the consist changes.
  * @param v First vehicle of the consist.
@@ -87,47 +135,11 @@
 
 	// store consist weight in cache
 	v->u.rail.cached_weight = weight;
+
+	/* Now update train power (tractive effort is dependent on weight) */
+	TrainPowerChanged(v);
 }
 
-/**
- * Recalculates the cached total power of a train. Should be called when the consist is changed
- * @param v First vehicle of the consist.
- */
-void TrainPowerChanged(Vehicle* v)
-{
-	Vehicle* u;
-	uint32 power = 0;
-
-	for (u = v; u != NULL; u = u->next) {
-		const RailVehicleInfo *rvi_u;
-		bool engine_has_power = true;
-		bool wagon_has_power = true;
-
-		/* Power is not added for articulated parts */
-		if (IsArticulatedPart(u)) continue;
-
-		if (IsLevelCrossingTile(u->tile)) {
-			if (!HasPowerOnRail(u->u.rail.railtype, GetRailTypeCrossing(u->tile))) engine_has_power = false;
-			if (!HasPowerOnRail(v->u.rail.railtype, GetRailTypeCrossing(u->tile))) wagon_has_power = false;
-		} else {
-			if (!HasPowerOnRail(u->u.rail.railtype, GetRailType(u->tile))) engine_has_power = false;
-			if (!HasPowerOnRail(v->u.rail.railtype, GetRailType(u->tile))) wagon_has_power = false;
-		}
-
-		rvi_u = RailVehInfo(u->engine_type);
-
-		if (engine_has_power) power += rvi_u->power;
-		if (HASBIT(u->u.rail.flags, VRF_POWEREDWAGON) && (wagon_has_power)) {
-			power += RailVehInfo(u->u.rail.first_engine)->pow_wag_power;
-		}
-	}
-
-	if (v->u.rail.cached_power != power) {
-		v->u.rail.cached_power = power;
-		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
-		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
-	}
-}
 
 /**
  * Recalculates the cached stuff of a train. Should be called each time a vehicle is added
@@ -231,9 +243,7 @@
 	// store consist weight/max speed in cache
 	v->u.rail.cached_max_speed = max_speed;
 
-	TrainPowerChanged(v);
-
-	// recalculate cached weights too (we do this *after* the rest, so it is known which wagons are powered and need extra weight added)
+	// recalculate cached weights and power too (we do this *after* the rest, so it is known which wagons are powered and need extra weight added)
 	TrainCargoChanged(v);
 }
 
@@ -307,6 +317,7 @@
 	int curvecount[2] = {0, 0};
 	int sum = 0;
 	int numcurve = 0;
+	int max_te = v->u.rail.cached_max_te; // [N]
 
 	speed *= 10;
 	speed /= 16;
@@ -407,6 +418,7 @@
 				force = power / speed; //[N]
 				force *= 22;
 				force /= 10;
+				if (mode == AM_ACCEL && force > max_te) force = max_te;
 				break;
 
 			case RAILTYPE_MAGLEV:
@@ -415,7 +427,8 @@
 		}
 	} else {
 		//"kickoff" acceleration
-		force = max(power, (mass * 8) + resistance);
+		force = (mode == AM_ACCEL && v->u.rail.railtype != RAILTYPE_MAGLEV) ? min(max_te, power) : power;
+		force = max(force, (mass * 8) + resistance);
 	}
 
 	if (force <= 0) force = 10000;

--- a/train_gui.c	Thu Dec 28 11:52:12 2006 +0000
+++ b/train_gui.c	Thu Dec 28 13:18:07 2006 +0000
@@ -232,6 +232,13 @@
 	DrawString(x,y, STR_PURCHASE_INFO_SPEED_POWER, 0);
 	y += 10;
 
+	/* Max tractive effort - not applicable if old acceleration or maglev */
+	if (_patches.realistic_acceleration && e->railtype != RAILTYPE_MAGLEV) {
+		SetDParam(0, ((rvi->weight << multihead) * 10 * rvi->tractive_effort) / 256);
+		DrawString(x, y, STR_PURCHASE_INFO_MAX_TE, 0);
+		y += 10;
+	}
+
 	/* Running cost */
 	SetDParam(0, (rvi->running_cost_base * _price.running_rail[rvi->running_cost_class] >> 8) << multihead);
 	DrawString(x,y, STR_PURCHASE_INFO_RUNNINGCOST, 0);
@@ -939,7 +946,10 @@
 	SetDParam(2, v->u.rail.cached_max_speed);
 	SetDParam(1, v->u.rail.cached_power);
 	SetDParam(0, v->u.rail.cached_weight);
-	DrawString(x, 25, STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED, 0);
+	SetDParam(3, v->u.rail.cached_max_te / 1000);
+	DrawString(x, 25, (_patches.realistic_acceleration && v->u.rail.railtype != RAILTYPE_MAGLEV) ?
+		STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED_MAX_TE :
+		STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED, 0);
 
 	SetDParam(0, v->profit_this_year);
 	SetDParam(1, v->profit_last_year);

--- a/vehicle.h	Thu Dec 28 11:52:12 2006 +0000
+++ b/vehicle.h	Thu Dec 28 13:18:07 2006 +0000
@@ -62,6 +62,7 @@
 	// cached values, recalculated when the cargo on a train changes (in addition to the conditions above)
 	uint32 cached_weight;     // total weight of the consist.
 	uint32 cached_veh_weight; // weight of the vehicle.
+	uint32 cached_max_te;     // max tractive effort of consist
 	/**
 	 * Position/type of visual effect.
 	 * bit 0 - 3 = position of effect relative to vehicle. (0 = front, 8 = centre, 15 = rear)