In message , Harry Bloomfield
writes

Many people do not understand volts drop and just how serious a problem
it can be at such low voltages. They base their calculations simply on
the current rating of the cable and even the pros ignore volts drop.

It is a problem those of us involved with old toy trains are well aware
of, using up to, say, 20v/5amp, but more usually 12-15v/1amp. Even with
longer track lengths (36 inches) and good, tight rail connections, the
difference across an oval can be substantial, so multiple feeds are
required, using good quality heavy duty wiring, with soldered
connections. None of you needed to know that :-)

--
Graeme