N-Scale Signals

I have recently decided to put in a system of signals on my layout. Went and purchased what was described as N-Scale signals off of EBay, however the size of the signals look way to big to be the correct fit. They look more like HO signals.

Need to know any brands or kits out there that would be great to use with the correct dimensions.

What exactly would be the correct dimensions in N-Scale for Signals? Looking mostly into placing D-Type style signals on the layout.

What dimensions would the crossing signals be?

Thanks for any advice you can give.

Some prototype examples:

1903 PRR standard plan semphore signal

http://prr.railfan.net/signalstandards/standards.cgi?plan=8-S--&frame=YES&sortdir=up&sortby=1&rr=all

and a 3 arm signal

http://prr.railfan.net/signalstandards/standards.cgi?plan=300-S5-0&frame=YES&sortdir=up&sortby=1&rr=all

Position Light signal 1952 standard plans

http://prr.railfan.net/signalstandards/standards.cgi?plan=S-400-F&frame=YES&sortdir=up&sortby=1&rr=all

from this site for more:

http://prr.railfan.net/signalstandards/standards.cgi

Sunrise N scale signals are the correct, but I believe they are not being made currently. Most based on Southern Pacific.

Atlas G type signals and NJ international signals are the correct size and they look good and work well.