©
minhtu: 1 004 Entry signal (lower quadrant semaphore signal)
©
minhtu: 1 005 Entry signal (lower quadrant semaphore signal)
©
minhtu: 1 006 Entry signal (lower quadrant semaphore signal)
©
minhtu: 1 008 Starting signals (lower quadrant semaphore signal)
©
minhtu: 1 007 Starting signals (lower quadrant semaphore signal)
©
minhtu: 1 009 Starting signals (lower quadrant semaphore signal)
©
minhtu: 1 010 Distant signal to entry signal (lower quadrant semaphore signal)
©
minhtu: 1 011 Distant signal to entry signal (lower quadrant semaphore signal)
©
minhtu: 1 012 Distant signal to entry signal (lower quadrant semaphore signal)