global var 0x86 (driving side); game settings flag 0x1B (train_signal_side)
0x86 == 0 && 0x1B == 0 --> driving left; signals left
0x86 == 0 && 0x1B == 1 --> driving left; signals right
0x86 == 1 && 0x1B == 0 --> driving right; signals right
0x86 == 1 && 0x1B == 1 --> driving right; signals left