OO scale signals

With regard to position light ground signals, there is a subtle difference between the older ones as depicted by the Eckon ES24 and more recent practise.

Originally stop was indicated by a red and a white light arranged horizontally and proceed at caution to the next stop signal was indicated by two white lights displayed at 45 degrees.

Nowadays the signal to stop is often given by two horizontal red lights, this being achieved by the light in the corner changing colour from white to red.

If you model modern image you may want to substitute a bi-colour LED for the white in the corner. This has the ability to change from red to white if you reverse the polarity of the supply or in the case of three wire LEDs, use a different connection. For this you need to devise some nifty wiring.

The 3mm red/white LED can be obtained from a limited number of suppliers.

Another way of displaying limit of shunt is to have a PLGS which displays two horizontal red lights permanently with the top light blanked off.

Also PLGS are often mounted on gantries or on signal posts with the red blanked off. In this case they only display proceed at caution to the next stop signal. the red lense on the main signal display indicates stop, of course.

Colombo

QUOTE (Colombo @ 22 Feb 2009, 17:47) <{POST_SNAPBACK}>Also PLGS are often mounted on gantries or on signal posts with the red blanked off. In this case they only display proceed at caution to the next stop signal. the red lense on the main signal display indicates stop, of course.

Sorry not quite true. Yellow on the main aspect indicates proceed at caution to the next stop signal or to a buffer stop. Two white lights alongside or below a main red aspect is known as a subsidiary aspect and indicates proceed at a safe speed to stop short of any obstruction that comes into view. This includes another train standing in a plaform or a position light ground signal showing a danger aspect. The subsidiary aspect is only illuminated as the train closely approaches it, to ensure that it has been slowed down.

If a main route (yellow, double yellow or green) is set to pass a position light ground signal then the latter will always be "preset" to show two white lights so as to avoid the driver seeing a red aspect.

QUOTE (Colombo @ 22 Feb 2009, 17:47) <{POST_SNAPBACK}>With regard to position light ground signals, there is a subtle difference between the older ones as depicted by the Eckon ES24 and more recent practise.

Originally stop was indicated by a red and a white light arranged horizontally and proceed at caution to the next stop signal was indicated by two white lights displayed at 45 degrees.

Nowadays the signal to stop is often given by two horizontal red lights, this being achieved by the light in the corner changing colour from white to red.......
As far as I am aware, the Eckon ES24 can show the more recent style by fixing red and white LEDs to the 'light pipe' going to the common 'lens'.

QUOTE ......The 3mm red/white LED can be obtained from a limited number of suppliers.....
So with the LED under the baseboard it does not necessarily have to be a 3mm one; this may give a wider range of choice.

The only GPLs and Anciliary lights I've seen modelled with LEDs actually in the head used surface-mounting (SMT)chips fixed in home-made Plasticard heads. These are described in "Model Railway Journal" No.171 published by Wild Swan Publications in 2006, on pages 311-317 in an article 'Scratchbuilding a modern bracket signal'. The signals described are used on the 'Widnes Vine Yard' layout of the Wirral Finescale Modellers, and are remarkable for their accuracy to the prototype.

And there is a full description of making multiple 'feathers' as well, also using SMT LEDs.

Regards,
John Webb