(lnd_mobtype): New.

(lnd_path): Use it.
(lnd_mobcost): Use it, remove last parameter.  Callers changed.  This
fixes mobility use of trains when retreating, both for retreat orders
and for failed morale checks.
(retreat_land1): Fix test for impassable terrain.  Before, trains
could retreat off rail.
(lnd_take_casualty): Test for impassable terrain.  Before, trains
could retreat off rail.

include/land.h

@@ -201,7 +201,8 @@ extern int lnd_interdict(struct emp_qelem *, coord, coord, natid);
 extern void lnd_sel(struct nstr_item *, struct emp_qelem *);
 extern int lnd_check_mines(struct emp_qelem *);
 extern double lnd_pathcost(struct lndstr *, double);
-extern double lnd_mobcost(struct lndstr *, struct sctstr *, int);
+extern int lnd_mobtype(struct lndstr *);
+extern double lnd_mobcost(struct lndstr *, struct sctstr *);
 extern char *lnd_path(int, struct lndstr *, char *);
 
 extern int attack_val(int, struct lndstr *);

src/lib/subs/attsub.c

@@ -1038,7 +1038,8 @@ ask_olist(int combat_mode, struct combat *off, struct combat *def,
 	switch (combat_mode) {
 	case A_ATTACK:
 	    mobcost = lnd_pathcost(&land,
-				   att_mobcost(off->own, def, MOB_MARCH));
+				   att_mobcost(off->own, def,
+					       lnd_mobtype(&land)));
 	    if (land.lnd_mobil < mobcost) {
 		pr("%s does not have enough mobility (%d needed)\n",
 		   prland(&land), (int)ceil(mobcost));
@@ -1530,7 +1531,8 @@ att_reacting_units(struct combat *def, struct emp_qelem *list, int a_spy,
 	    continue;
 
 	getsect(def->x, def->y, &dsect);
-	if (!BestLandPath(buf, &sect, &dsect, &pathcost, MOB_MARCH))
+	if (!BestLandPath(buf, &sect, &dsect, &pathcost,
+			  lnd_mobtype(&land)))
 	    continue;
 
 	mobcost = lnd_pathcost(&land, pathcost);
@@ -2529,7 +2531,8 @@ take_move_in_mob(int combat_mode, struct llist *llp, struct combat *off,
     switch (combat_mode) {
     case A_ATTACK:
 	mobcost = lnd_pathcost(&llp->land,
-			       att_mobcost(off->own, def, MOB_MARCH));
+			       att_mobcost(off->own, def,
+					   lnd_mobtype(&llp->land)));
 	new = llp->land.lnd_mobil - mobcost;
 	if (new < -127)
 	    new = -127;

src/lib/subs/lndsub.c

@@ -162,7 +162,7 @@ lnd_take_casualty(int combat_mode, struct llist *llp, int cas)
     int taken;
     int nowhere_to_go = 0;
     struct sctstr rsect;
-    double mobcost;
+    double mobcost, bmcost;
     signed char orig;
     int mob;
 
@@ -227,12 +227,16 @@ lnd_take_casualty(int combat_mode, struct llist *llp, int cas)
 		    continue;
 		if (sect.sct_type == SCT_MOUNT)
 		    continue;
+		mobcost = lnd_mobcost(&llp->land, &rsect);
+		if (mobcost < 0)
+		    continue;
 		++nowned;
 		civs = sect.sct_item[I_CIVIL];
 		if (civs > biggest) {
 		    biggest = civs;
 		    bx = sect.sct_x;
 		    by = sect.sct_y;
+		    bmcost = mobcost;
 		}
 	    }
 	    if (!nowned)
@@ -242,8 +246,7 @@ lnd_take_casualty(int combat_mode, struct llist *llp, int cas)
 		llp->land.lnd_x = bx;
 		llp->land.lnd_y = by;
 		getsect(bx, by, &rsect);
-		mobcost = lnd_mobcost(&llp->land, &rsect, MOB_MARCH);
+		mob = llp->land.lnd_mobil - (int)bmcost;
-		mob = llp->land.lnd_mobil - (int)mobcost;
 		if (mob < -127)
 		    mob = -127;
 		orig = llp->land.lnd_mobil;
@@ -998,7 +1001,7 @@ lnd_pathcost(struct lndstr *lp, double pathcost)
 	effspd *= lp->lnd_effic * 0.01;
 
     /*
-     * The return value must be pathcost times a factor that depends
+     * The return value must be PATHCOST times a factor that depends
      * only on the land unit.  Anything else breaks path finding.  In
      * particular, you can't add or enforce a minimum cost here.  Do
      * it in sector_mcost().
@@ -1006,10 +1009,17 @@ lnd_pathcost(struct lndstr *lp, double pathcost)
     return pathcost * 5.0 * speed_factor(effspd, lp->lnd_tech);
 }
 
-double
+int
-lnd_mobcost(struct lndstr *lp, struct sctstr *sp, int mobtype)
+lnd_mobtype(struct lndstr *lp)
 {
-    return lnd_pathcost(lp, sector_mcost(sp, mobtype));
+    return (lchr[(int)lp->lnd_type].l_flags & L_TRAIN)
+	? MOB_RAIL : MOB_MARCH;
+}
+
+double
+lnd_mobcost(struct lndstr *lp, struct sctstr *sp)
+{
+    return lnd_pathcost(lp, sector_mcost(sp, lnd_mobtype(lp)));
 }
 
 int
@@ -1101,11 +1111,7 @@ lnd_mar_one_sector(struct emp_qelem *list, int dir, natid actor,
 	}
 	llp->land.lnd_x = newx;
 	llp->land.lnd_y = newy;
-	if (lchr[(int)llp->land.lnd_type].l_flags & L_TRAIN) {
+	llp->mobil -= lnd_mobcost(&llp->land, &sect);
-	    llp->mobil -= lnd_mobcost(&llp->land, &sect, MOB_RAIL);
-	} else {
-	    llp->mobil -= lnd_mobcost(&llp->land, &sect, MOB_MARCH);
-	}
 	llp->land.lnd_mobil = (int)llp->mobil;
 	llp->land.lnd_harden = 0;
 	putland(llp->land.lnd_uid, &llp->land);
@@ -1277,10 +1283,7 @@ lnd_path(int together, struct lndstr *lp, char *buf)
 	return 0;
     }
     getsect(lp->lnd_x, lp->lnd_y, &sect);
-    if (lchr[(int)lp->lnd_type].l_flags & L_TRAIN)
+    mtype = lnd_mobtype(lp);
-	mtype = MOB_RAIL;
-    else
-	mtype = MOB_MARCH;
     cp = BestLandPath(buf, &sect, &d_sect, &dummy, mtype);
     if (!cp) {
 	pr("No owned %s from %s to %s!\n",

src/lib/subs/retreat.c

@@ -458,11 +458,10 @@ retreat_land1(struct lndstr *lp, char code, int orig)
 	newy = ynorm(lp->lnd_y + dy);
 
 	getsect(newx, newy, &sect);
-	if ((sect.sct_type == SCT_WATER) ||
+	mobcost = lnd_mobcost(lp, &sect);
-	    (sect.sct_type == SCT_MOUNT) ||
+	if (mobcost < 0
-	    (sect.sct_type == SCT_SANCT) ||
+	    || sect.sct_type == SCT_MOUNT
-	    (sect.sct_type == SCT_WASTE) ||
+	    || sect.sct_own != lp->lnd_own) {
-	    (sect.sct_own != lp->lnd_own)) {
 	    wu(0, lp->lnd_own, "%s %s,\nbut could not retreat to %s!\n",
 	       prland(lp),
 	       conditions[findcondition(code)].desc[orig],
@@ -471,7 +470,6 @@ retreat_land1(struct lndstr *lp, char code, int orig)
 		putland(lp->lnd_uid, lp);
 	    return 0;
 	}
-	mobcost = lnd_mobcost(lp, &sect, MOB_MARCH);
 	lp->lnd_x = newx;
 	lp->lnd_y = newy;
 	lp->lnd_mobil -= mobcost;