Method UpdateSpeed

src/train_cmd.cpp:3019–3029

* This function looks at the vehicle and updates its speed (cur_speed * and subspeed) variables. Furthermore, it returns the distance that * the train can drive this tick. #Vehicle::GetAdvanceDistance() determines * the distance to drive before moving a step on the map. * @return distance to drive. */

 * @return distance to drive.
 */
int Train::UpdateSpeed()
{
	switch (_settings_game.vehicle.train_acceleration_model) {
		default: NOT_REACHED();
		case AM_ORIGINAL:
			return this->DoUpdateSpeed(this->acceleration * (this->GetAccelerationStatus() == AS_BRAKE ? -4 : 2), 0, this->GetCurrentMaxSpeed());

		case AM_REALISTIC:
			return this->DoUpdateSpeed(this->GetAcceleration(), this->GetAccelerationStatus() == AS_BRAKE ? 0 : 2, this->GetCurrentMaxSpeed());
	}
}

/**
 * Trains enters a station, send out a news item if it is the first train, and start loading.