I got a set of train horns from a buddy and don’t know a hole lot about it all, But I LOVE TO SCARE THE CRAP OUT OF PEOPLE…LOL The Set he gave me was a 3 horn set and the only righting on them is on the backs of each horn they say GG. I hooked them up in my semi truck and they are loud but I want Louder. I ran a 3/8 line from my truck air tank (125psi) up into my cab and put a 3/8 quarter turn gate valve from the plumbing section at ace hardware…lol Then I ran 3/8 air line from the valve to the horn, and thats my set up. Its pretty loud but how can I make it louder and what kind of horn says GG on the back of it. Thanks for any help Guys !!
Only real way to get louder is purchase a set of Nathan Airchimes if you dont mind spending the money.
If money is limited then you could look into a set of shockers with the upgrade to 1/2in airlines.
But sorry to say those three trumpet horns are not as loud as advertised and not really anyway to make them louder.
The only horns I know that start with G are Grover (semi truck horns?).
Higher pressure will usually make horns louder but it can also distort the sound and reduce the life of the horn’s diaphram.
Get a set of Shockers!:D:D:D:D
Exactly 
Just bought some k3la’s, is there a line and fitting kit for that setup?
Welcome to the forum. Hornblasters has kits without horns under “On Board Air Systems”. Those horns are fairly air hungry so get a kit with a large tank, hoses & fittings. The fittings & hoses should be at least 3/8" ID.
Yeah, Hornblasters has it all. If you call em up, they’ll get you fixed up.
I bought a tank, valve, airline, and fitting kit for the tank from them.