Steam Locomotive

A steam-powered locomotive with cylinders, drivers, and a boiler.

• Kind: SteamLocomotive
• Extends: Car

Fields

All Car fields are inherited, but a steam locomotive positions itself from positionHead, positionTail, and wheelsets instead of length, truckSeparation, and the bolster insets. truckSeparation, bolsterInsetFront, and bolsterInsetRear are unused here and hidden by the Definition Editor. See Car Geometry. Additional fields:

length

float

Read-only on a steam locomotive: computed as positionHead - positionTail. A value written here has no effect. See Car Geometry.

mainDriverIndex

int

Index of the main driver in the wheelsets list. Curve capability is measured from it; an index that doesn’t resolve falls back to a generic default. See Car Geometry.

maximumBoilerPressure

float

Maximum steam pressure (PSI).

pistonDiameterInches

float

Cylinder bore (inches).

pistonStrokeInches

float

Piston stroke (inches).

positionHead

float

Front coupler pivot, in meters from the model origin, measured positive toward the front. See Car Geometry.

positionTail

float

Rear coupler pivot, in meters from the model origin. length is derived as positionHead - positionTail. See Car Geometry.

publishedTractiveEffort

int

Tractive effort in pounds.

tenders

object = {}

The tenders this locomotive can be paired with. Each key is the identifier of a Car definition; each value is a pairing with a drawbarDistance, a priority, and an optional builderPhoto.

drawbarDistance is the distance in meters between the two frames. 0 falls back to the standard coupler separation, so a tender that’s dimensionally interchangeable with the stock one needs no measurement.

priority orders the list, lowest first. The locomotive spawns with the first tender in that order when nothing else picks one. A locomotive with no entries is a tank engine.

builderPhoto names the Texture definition holding a photo of the locomotive coupled to that tender, shown on the purchase screen. A pairing without one falls back to the locomotive’s own builderPhoto, so give the default pairing that field and let the rest override it.

"tenders": {
  "rr/lt-462-p48": { "drawbarDistance": 0 },
  "rr/lt-462-p48b": {
    "drawbarDistance": 0.35,
    "priority": -1,
    "builderPhoto": "./ls-462-p48--lt-462-p48b"
  }
}

The paired car’s carType must start with LT. Replaces the older single tenderIdentifier field.

totalHeatingSurface

float = 3000

Total heating surface area (sq ft).

weightOnDrivers

float

Weight on driving wheels (pounds).

See Wheelset in Common Types for wheelset field details.

wheelsets

Wheelset[] = []

The wheels the locomotive rides on, authored front to rear. See Car Geometry for how offsets position the locomotive.