On Apr 9, 12:50*am, spsffan wrote:

No. 6 batteries

It rather makes sense, as I seem to recall them mostly in science labs
and science experiment kits of the kind marketed to adolescent boys. I
seem to recall that my brother used one with a practice telegraph key,
which had a flashlight bulb to give feedback in learning Morse Code.
Stuff like that!

The "How & Why Wonder Book on Electricity" had projects for kids using
a No. 6 dry cell. They taught about series and parallel wiring.

I remember wrapping wire around a big nail to make an eloctromagnet,
and turning it off and on to pick up papercliops. But the nail
retained some of its magnetism.

I _think_ a battery cost about $1 back then and it would last
forever. The local store had all the knife switches, light sockets,
1.5V screw maps that I could want for my experiments. Connecting a 6V
lantern battery to a 1.5V burned it out in a flash.

Returning to rail, many places were lit by five bulbs in series off
the 600V traction power. If a bulb burned out they all did. But I
think some fancy trains had special circuits to bypass a dead bulb.