Re: First Automatic signal?

[James Robinson <Wascana@my-deja.com>]

signal_spotter@my-deja.com wrote:

> "Automatic signalling was first tried in USA and the first system on a
> British main line was on the London and South Western Railway. It began
> on 20th April, 1902."

Ignoring mechanical arrangements, automatic signalling was enabled with
the invention of the electric track circuit:

from: http://www.ccrc.wustl.edu/~jpgs/transport/rail/signal/na2.html

"The track circut was invented by William Robinson which enabled the
automatic block signal. Robinson's block signal was first demonstrated
in model form in 1870 and supsequently installed on the Philadelphia and
Erie Railroad at Kinzua Pennsylvania. It consisted of an electrically
operated disc located on top of small signal huts, and was based on an
open track circuit. He improved on this with the closed track circuit,
replacing the earlier installation in 1872 [BrMc81, Ph93]."