Puggins
Explorer
House Orien's Lightning Rails, the rails themselves, are primarly built using conductor stones, wondrous magical items.
People would steal them. In droves. They would steal entire lines. Just to sell back to House Orien through fences, or to anyone who didn't want the rails running. No matter how many examples House Orien made, there would be hordes of desperate people willing to do it because the act of the theft itself, out in the middle of nowhere, was very low risk. That would pretty much be the end of the rails.
I did not see where the Eberron Campaign Setting book explains why this does not occur. Did I miss it? Did some other book mention it?
Well, I'd ask the same thing about the rail system here in our world. Someone can take a jaunt over to an isolated portion of the railroad track, rip it out and watch trains crash. So what's stopping hordes of people from calling Amtrak or NTSB and demanding $1,000,000 in unmarked bills?
Yes, we have the FBI and the police. Aundair, on the other hand, has the college of mages (who no doubt have all sorts of divination spells ready for use) and its army, which isn't prohibited from working domestically.
Also keep in mind that railways worked just fine in the late 19th century, when the nation's law enforcement arm had a tiny fraction of the resources they have today.
Offhand, I'd say that Orien would have some sort of magical mark affixed to each stone, making it relatively straightforward to track. Punishment would be severe- certainly death, possibly worse.
I don't think it would be much a problem.