Ya I'm trying to power my 3 ISEs that power my coal farm with steam. At first it was very inefficient because I had only one pipe supplying steam to all 3. Now I have each of them on an individual pipe, with ISEs powering the emerald extraction pipes. For whatever reason though, they barely get anything. They might get up to 40 rf/t for a second and then drop down to 13. I'm pretty sure its because I have each pipe line supplying 2 engines, the extraction pipe and the pipe to the engine powering the farm, and how far the steam has to travel, despite using golden pipes all the way down. I'm thinking of building a liquid fueled boiler much closer to them and pipe in the creosote I have stored up into it. I have over 20 thousand buckets of creosote stored. It's beginning to become an issue. Building more and more iron tanks would take up a lot of space and a lot of resources.
Try placing your steam engines directly on the face of the boiler, and then just transporting the power wherever you need it (unless you want to buffer steam for peak consumption). Failing that (i.e. if you're short on redstone, but have plenty of gold), each engine might need two separate lines of pipes going all the way from the boiler to the engines. It's been too long since I've played with BC+RC for me to remember how many pipe lines are needed, although I vaguely remember reading about some BC addon that added an even faster fluid pipe that I want to say was able to fully supply an industrial steam engine with only one line of pipes. I don't remember very clearly, though; maybe it was two engines per pipe line.
Research time!
According to
Railcraft's wiki, the industrial steam engine requires 40 mB/t of steam in order to produce the full 80 RF/t.
Documentation on Buildcraft is hard to find; however,
a couple of sources peg the golden pipe's throughput at 80 mB/t, enough to fully supply two ISEs. For some reason, I remember the reverse of this being the case- two lines of pipes being required per engine- but apparently that's been changed.
So, my guess is that either you're not producing enough steam, in which case add more fireboxes and/or tanks to your boiler, or you've got a bottleneck somewhere in your pipe line. Do you have a wooden fluid pipe connecting to your boiler, by any chance? If so, there's your problem. Remove it and replace it with a gold pipe. The boiler outputs steam automatically.