Why the number is three nines
Britain introduced the world's first EMERGENCY telephone number in 1937, after a fire in a London house killed five women. A neighbour had tried to telephone the fire brigade and was left holding on in the ordinary queue for the operator. The outcry produced a number that jumped the queue and rang a bell in the exchange.
Three nines was picked for reasons that sound strange today. On a rotary dial, the 9 sits right beside the finger stop, so it could be found by touch in the dark or in smoke. And three nines were very unlikely to be dialled by accident, whereas a fault on a line could easily produce a single short pulse and summon help to nowhere.
The first person you speak to
You do not reach a FIREFIGHTER or a PARAMEDIC. You reach a DISPATCHER in a CONTROL room, whose job is to work out what has happened, where exactly you are, and which service to send — while you are frightened and quite possibly not making much sense.
Then they keep talking while the help drives. Dispatchers give chest-compression instructions down the phone, talk strangers through stopping serious bleeding, and have helped deliver a great many babies without ever being in the room. It is the least visible job in the service and one of the hardest.
Most call-outs are not fires
A modern FIREFIGHTER spends relatively little time putting out fires. Smoke alarms, better wiring and stricter building rules have cut house fires dramatically, and the job has widened to fill the space: cutting people out of crashed cars, pumping out floods, rescuing walkers and animals, and attending medical emergencies when a crew happens to be closer than an ambulance.
The name has stayed because everyone understands it, but a fire engine today is closer to a general-purpose RESCUE vehicle that happens to carry a large tank of water.
Ambulance work has gone the same way. A large share of what crews attend is not immediately life-threatening, so every CALLOUT is graded before anyone is sent, and the most serious ones are pushed to the front of a long queue.
A uniform is written in shorthand
Rank is legible once you know the code. A CONSTABLE carries a number on the shoulder. A SERGEANT has stripes. A DETECTIVE frequently wears no UNIFORM at all, which is rather the point. A LIFEGUARD wears red and yellow because that combination means patrolled water on beaches worldwide.
None of the design is decorative. High-visibility jackets are that particular yellow-green because human eyes are more sensitive to it than to any other colour, and on many incidents a helmet colour tells everyone at a glance who is in charge.
Training for a day that may never come
Most of this work is preparation. Crews drill constantly, rehearse disasters they hope never to attend, and maintain equipment that may sit untouched for years. A LIFEGUARD can work an entire season without a single serious RESCUE, and that is the desired result, not a wasted summer.
For the machines themselves — the engines, ambulances, lifeboats and helicopters — our emergency vehicles puzzle has those. This grid is about the people who climb into them at three in the morning.