Any boby knows of "points"; signalling system of the older railway?

Question

what are A1 & A1A categories?

more datails of this namings are wellcome

Answer 1

What are you talking about? Who is Boby? Of course more details are welcome. I am sure your teacher/professor likes detailed answers. Why can't you just do a web search? I found the links below in less than two minutes. Don't be lazy.

Answer 2

Mr. Hoghead has given the best answer by far regarding signals...

I was just going to add, the A1A designations you are listing sound more like railroad locomotive truck designations than anything else. An A1A was a 3 axle truck, with two powered axles and an idler (non powered) in the center... There were many types, like B (two powered axles), C (three powered axles) and so on.. A letter was a powered axle, and number was an un-powered axle -- both the letter and number in relation to the numer of axles.

Answer 3

I have heard of no such systems on American rail roads.  Perhaps these devices are particular to European railways.

Most class 1 rail roads these days are using the conventional "search light" type of signal heads.  These are the common round signal heads found on signal bridges and trackside signal masts.  Most display their aspects via a single lens.  There are other signal heads with multiple lenses and varying shapes.

The fore runner of these types of signals were called "semiphore" signals.  These were also found on signal bridges and signal masts.  The primary piece of these devices was an "arm", called a blade, and it was a moving part of an electro- mechanical device.

The position of the blades displayed the aspect of the signal that conveyed information to the train crew.

With the arm horizontal, the indication was stop.  At an angle the signal conveyed the same information as a "yellow" signal does today.  With the blade perpendicular, the indication was clear.

There were two types of semiphore signals I know of.  The first is called a "lower quadrant" sigal, where the blades conveying yellow or clear move below the horizontal stop position, and the upper quadrant with the blades moving upwards from the stop position.

In addition, the blades had three lenses on the opposite side of the extended portion of the blade, red, yellow, green.  There was a stationary light behind them, and as the blades moved to the correct position, the light would be behind one of the lenses.  This is why, when one talks of their indications, the blades were the daytime indicators and the lights were the night time indicators.  Although the blades were illuminated by the engine's head light at night, the lights were seen at a much greater distance.

The last ones that I worked with were on the Siskiyou subdivision of the Oregon division of the late, great SP.  This has now been short-lined to the CORP, or California Oregon Pacific.  I don't know if they are still in use.

Addendum:  DTTRR89ACE should have ten points coming his way.  I knew that such wheel arrangements existed but I never knew how they were designated until today.  These were wheel arrangements used on the EMD "E" class of engine and the Alco "PA" class.  I would assume Baldwin also manufactured engines with this type of truck.