Thank you Mark (mmthrax), and CapnMac82 for your compliments.
CapnMac82
Gets better and better.
per my previous question, what I was envisioning were some laminate disks with numerals that would fit on the bosses of the handles to where the switches could be numbered in sequence.
Which could then be "codified" with a series of .AND. circuits. So that S2 is only powered if S1 is powered, and so on. Which would "collapse" if say S3 out of S8 were deenergized. Only problem with that, is the loads on reenergizing. Which is why the smart kids use programmable controlers. I'm more of a breadboard it to see if it works type...
Good ideas. Not sure exactly how to impart the sequence intsructions. The general plan is to have a list 1 to n. Like:
1/ Switch CHANGEOVER to NORMAL.
2/ Turn CONTROL switch to CONTROL.
3/ Switch TRAFFIC CONTROL to NORMAL. Wait till GATES MOVEABLE lamp is ON.
4/ Switch GATES 1-4 to CLOSE.
etc.
Step 3 triggers an alarm bell and flashing amber traffic lights for 10-15 seconds before the red traffic lights turn red. At this point both ROAD LIGHTS RED and GATES MOVEABLE lamps light up. Gates 1-4, via a relay, become enabled. Not until all four gates are closed does another relay become energized to enable LIFT SPAN LOCK OPERABLE lamp lights up.....and so the sequence goes.
Some relays are latched, isolating and enabling the sequence to one section only. This disables other switches (no power).
Operating the bridge uses momentary pushbuttons, they too are hooked up so no two or more buttons pressed simultaneously will make a difference. . . except a disabled action.
There is a lot to work out when trying to make something child-proof.
Some operators will feel too challenged and will abandon sequence halfway. Or could not be bothered to go further after the boat has traversed under the bridge. A timer will then disable the display and a museum staff member will have to complete the sequence to reset it.
If all this gets too much of a hassle. The alternative is to have the visitor ask at the desk (nearby) to operate the bridge, and a staff member will supervise.