Variable:vehicle flags

From TTWiki

Various flags that define the vehicles behaviour.

Bit_0 
Two coupled vehicles face opposite directions (used by all diesel and electrical engines)
Bit_1 
Has a driving cab (trains with driving cabs or engines on either side don't turn around at the end of the track, but drive backwards)
Bit_2 
Front axis can share bogie (field_24[0] defines shared bogie type)
Bit_3 
Rear axis can share bogie (field_24[1] defines shared bogie type)

When Bit 2 and 3 are set, field_24[0] is for front bogie, field_24[2] for rear and field_24[1] is the actual vehicle.

Bit_4 
Auto-placing evenly spreads new vehicles along the train, rather than just appending them (used only by TGV and Electra-Star power cars)
Bit_5 
Is a power car and explicitly requires a driving cab with Bit_1 set.
Bit_8
land vehicles: Vehicle can not drive backwards (used by all trucks and busses, buggy for trains)
planes: Use slope sprites for taxiing (used by old planes)
Bit_D
land vehicles: Controls the exhaust for an engine on its limit. If not set, the exhaust is continuous, otherwise it's more random (used by all steam engines).
planes: Vehicle is a helicopter
anytrack 
Can it run on any type of track? (used by all buses and trucks)
cancouple
land vehicles: There can not be more than one of these vehicles on a train (used by all road vehicles)
planes: Use slope sprites for landing (tilted backwards; used only by Concorde)
dualhead 
If the vehicle requires two locomotives (for example, the TGV)
noannounce 
If the news announcement disabled when this vehicle is invented
rackrail 
Can the vehicle use a rack rail?
refittable 
If the vehicle is refittable(mostly planes and passenger boats) (Refitting allows only mail, food, goods, and grapes. New capacity is passenger capacity divided by 2.5)