Adjust train gold refill time and modify fare calculation logic

- Reduced the train gold refill time from 600 to 300 ticks for faster resource replenishment.
- Updated fare calculation to use a base length bonus and adjusted congestion fare logic, ensuring that only the net congestion premium is added to the fare.

src/core/configuration/DefaultConfig.ts

@@ -371,7 +371,7 @@ export class DefaultConfig implements Config {
   }
   trainGoldRefillTime(): Tick {
     // Baseline: full refill in x ticks
-    return 600;
+    return 300;
   }
 
   trainStationMinRange(): number {

src/core/game/Railroad.ts

@@ -167,14 +167,15 @@ export class Railroad {
   }
 
   getFare(): bigint {
-    const baseLengthFare = 10;
-    const baseCongestionFare = BigInt(2000);
-    const lengthFare = BigInt(this.getLength() * baseLengthFare); // Base fare proportional to length
+    const baseLengthBonus = 10;
+    const baseCongestionFare = BigInt(1000);
+    const lengthFare = BigInt(this.getLength() * baseLengthBonus); // Base fare proportional to length
     // Busy railroads should be more expensive: each train adds a congestion premium
     const effectiveCongestion = Math.max(0, Math.round(this.congestionEma));
     const congestionFactor = BigInt(1 + effectiveCongestion); // 1,2,3,...
     const congestionFare = baseCongestionFare * congestionFactor;
-    return lengthFare + congestionFare;
+    const net = congestionFare > lengthFare ? congestionFare - lengthFare : 0n;
+    return net;
   }
 
   setRailTiles(tiles: RailTile[]) {