Touring - Maximum speed with trailer?

Does anyone know know how fast you can realistically and safely ride with a 2 child bike trailer attached to you bike, with say:
a) one or two kids
b) some non living cargo. ;)

How long is a piece of string.

Resonance is probably your biggest enemy.

Without working at it, I can average 12 mph with my 43lb grandson in his trailer and its just a cheap Wally World thing. That's on my Gary Fisher mountain bike, which is geared lower even than most touring bikes. I suppose, with better conditioning, replacing the front tire with a 1.5 slick as is on the back, and a lighter trailer, 15 mph wouldn't be too difficult.

Realistically, fully loaded with the goal of doing 6 hours on the bike and enjoying the rest of the day, 11mph. That's like brisk walking.

You think two kids in the back of a car is a headache. Try seating them shoulder to shoulder in a trailer. The poking and the potty breaks will drive you nuts.

i can get 40mph on the downhills with my 185lb grandfather in the trailer

When my nephew weighed only 30 or 40 pounds, I was amazed how little pulling the trailer increased my work load. I could easily cruise at my normal speed on a decent road. The problems came with braking and cornering. You have to begin to slow down sooner, and you needed to do corners carefully...but once you are cruising along, the trailer is no problem.

Two kids can share a trailer for hours...if ONE of them is sound asleep...otherwise...

There's so little difference at speeds between 10 and 15 mph, to me, it doesn't matter. slow down and enjoy.

Just got done doing 4 days 200 miles and yep, 10mph is a realistic target on flat terrain. This is the only pic I've got so far. 38lb kid, Two stuffed doggies, four books, water bottle, oreos, plus weight of Chariot carrier, plus his sleeping bag, his sleeping pad, headlamp, clothes, plus my stuff, so dragging 100lbs+ extra I'd say we were doing good.

Just got done doing 4 days 200 miles and yep, 10mph is a realistic target on flat terrain. This is the only pic I've got so far. 38lb kid, Two stuffed doggies, four books, water bottle, oreos, plus weight of Chariot carrier, plus his sleeping bag, his sleeping pad, headlamp, clothes, plus my stuff, so dragging 100lbs+ extra I'd say we were doing good.

Thats quite a load nice job :)

5 hours in a trailer wow.

What a stupid question. Trailers with young kids should stay on dedicated bike paths and the hell off the road. How fast can you go.... What if you hit a pot hole? What if your front wheel loses traction on a gravel shoulder? What if an enfeebled old person, a texting teenager, or cellphone-distracted soccer mom, or drunk T-bones you? Mere road rash to you can be broken bones and worse for your children. Use common sense or the best that will happen is that the State will take your children away.

Imagine the tragedy:

"How did you lose your children?"

"Well, I was pulling them in a trailer behind my bike while riding on a busy highway and some person didn't see them, ran them over, and killed them instantly."

"That's awful, did you sue?'

I've gone 43mph with 40-50lbs in a Bob trailer on a long down hill before, but looking back on it, I'm not sure that was the best idea. I think ~35 mph is pretty safe though. Generally rule of thumb that I try to use, is only go as fast as your willing to eat it at.