What is this called?

My break pedal got mushy so i started looking underneath and found this over the rear axle. It's two break lines that come together and its leaking from there.

Brake Tube Junction Block

Thank you

NP - always gotta help a fellow rail-roader out

Those look like they're going to be 'fun' to remove. Hopefully you get lucky. Douse the others in penetrating fluid for a few days (give them a few squirts as time goes on) and use line wrenches ...if they'll fit.

If I was doing it, I would remove the leaking line first. Then *carefully* inspect the actual flair to see if it's hairline-cracked. It's a double-flare in steel and steel doesn't really like to be double-flared. They often crack, sometimes they are ok but leak later on. And if ya overtighten new lines that can crack them as well. It's not an uncommon situation. There could also have been a piece of micro-grit under the line when it was installed. It was good at first, but now is leaking. If any of these are the case, then most likely just the affected line can be replaced. There might not be anything wrong with the junction block. The worst case scenario is you damage other lines during the attempted removal process. So the less you disturb ....

You'll probably need to run it through the 'bleed' process via a scan tool when you get it all back together to get firm pedal again. Might as well flush the entire system of old fluid. Your pedal will likely feel 'firmer' afterwards.

Good luck on the project.

Take a pair of side cutters and cut the steel line at the fitting than use a deep socket and ratchet to remove the fitting while holding the junction box with a pair of vise grips . Once the fitting is Broken loose it will come out easy. No penetrating fluid required

A little heat doesn’t hurt either.

What I wonder about , besides all the NY rust is all the lead ballast on the wheel rim, looks like the balance must be shot
If that is wheel weights , something is wrong
Could just be my old eyes seeing things?

fluid film, for real man, make that truck last.