Yes, this particular forum tends to be a bit quiet, perhaps because Buffett doesn't often trade as much as he has recently, and he has previously not been in the media spotlight as much as he seems to be now.
BRK is a big holding for me as I believe the price is undervalued despite the large sticker price for both a and b shares. Although the transition plans in case anything should happen to Mr. Buffett are somewhat up in the air, and there are supposed to be a few people that might be tapped to take the reigns in such an event, the next in line certainly doesn't command the respect and admiration that Mr. B does.
One appeal of the railroad stock BRK has taken a large position in, is supposed to be the link between coal mining and the end users or other transportation lines that take coal further along the chain. I do not recall where I read this idea, but that is supposed to be a primary reason for the purchase. Unfortunately, coal has a bad reputation for disturbing air quality and the ozone layer, so while the US is very coal rich, its use is clouded by these legitimate concerns.
My guess is that Mr. B will continue to look for future purchases abroad, where faster future growth is likely to be, plus, I believe he may still have an eye on currency valuations which would make foreign investments more attractive as well. Overall, his bets on currency have been more positive than negative although the gaff he made in currency not too long ago caught all the publicity.