Three of gfisher's Order Boards are interactive
<kuid:106916:10219> B&M Train Order Board
<kuid:106916:10312> CBQ Train Order Board
<kuid:106916:10303> SP Train Order Board
These can be used along with invisible tracks and triggers to setup a signal system but it ain't easy.
I've also experimented with these "manual" signals (changing some to right hand)
<kuid2:60850:24524:4> Sig UQ Combined 20ft LHS
<kuid2:353810:1888000:4> TGR semaphore signal, LQ, home, 20ft timber post
<kuid2:60850:24544:4> Sig UQ Combined TC 20ft LHS
<kuid2:60850:24523:3> Sig UQ Distant 20ft LHS
<kuid2:60850:24522:4> Sig UQ Home 20ft LHS
<kuid2:60850:24542:4> Sig UQ Home TC 20ft LHS
<kuid2:353810:1888005:4> TGR semaphore signal, LQ, home, 20ft timber post, RH
<kuid2:60850:24574:50> Sig UQ Combined TC Cantilever 15ft LHS
<kuid2:60850:24540:4> Sig UQ Home TC 15ft LHS
<kuid2:60850:24564:4> Sig UQ Combined TC Cantilever Sighting 15ft LHS
<kuid2:60850:24521:3> Sig UQ Distant 15ft LHS
<kuid2:60850:24520:4> Sig UQ Home 15ft LHS
At 15 to 20ft they look pretty good on pre-1900 and narrow gauge routes, add some signalmen's huts, signal men, kerosene cans, a telegraph line and it is pretty believable. Not sure how realistic it is.
BTW the ball signal is also available on the DLS <kuid:86661:24204> 2foot highball by slugsmasher. It is used on several Sandy River routes.
Hum, after scanning through hundreds of photos on the internet the only signals I saw were the Order Board style. However,
http://www.drgw.net/info/Signals I found some comments here and there that support the information in the link.
After a bit of searching I could not find the GRS signals listed in the above link available in Trainz. The nearest I found were norfolksouthern37's Safetran signals (from JR). If you are doing pre 1930ish you'd want his CLight series and if post 1930ish his NS series I think. Or you can stick with the invisible signals that klinger used.