I’m a railway buff and I was wondering do they still lay track?
I am not counting light rail, as in El Trains, Monorails, subways etc.
Sure they do. A new underground line was completed in Sydney a few years ago (the airport link), and another is soon to start:
http://www.raillink.nsw.gov.au/Project_Profile/projmenu.htm
Digging tunnels and constructing stations are the hardest bits. Laying the track is easy. 
I presume you are talking about long-distance railroads? There are several construction projects going on in Japan, mostly to replace existing railroads with high-speed tracks. This means constructing a completely new route because high-speed tracks cannot have sharp curves and level crossings. The Tokyo-Nagano high speed line was completed just in time for the Nagano Winter Olympics in 1998. There’s also an extention opening in Kyushu next spring.
The TGV network in France is forever expanding. Last year they opened the line from Paris to Marseilles which is amazing. It covers over 600km in under three hours! And the Eurostar service is essentially an extension of the TGV network. They’ve just opened the new high speed Channel Tunnel Rail link between the British end of the tunnel at Folkestone and London, cutting the journey time by around an hour. Of course, they should have done that over ten years ago at the same time as the rest of the project, but the sad truth is that the Brits are utterly useless at railways.
Desmostylus is correct but also missed the biggest rail project in Australia. In September the Adelaide Darwin rail line (1,420kms) crossing Australia north south was completed.
And for only 25 euros! The seats were pretty uncomfortable, though.
Tampa - Orlando Train
As for Freight Railroads in North America, the answer is really only short segments (<5Km) for sidings, spurs, bypasses (example: the proposed Chicago Region Environmental and Transportation Efficiency Project
http://www.starnewspapers.com/star/spbiz/here/x10here.htm )
are constructed today. In NY, I think the Oak Point Connection was one of the largest freight only projects in the last decade, and that was only a few miles along the Harlem River)
I guess us US railfans are just happy that the massive abandoments of the 60s-80s have petered out (indeed, way too much capacity was lost, and it takes forever to get it back [witness the the Rahway Valley RR restoration ], oftentimes as Passenger only (witness the Old Colony lines of Southeast Mass, or the Lackawanna Cutoff, or M.O.M. and so on). From time to time significant lengths of lines are still abandoned, but usually because they served a single large industry (oftentime a mine) that has closed. In the 80s was the disaster of Conrail’s ‘Brilliant’ scorched-earth policy, where many secondary lines were cut, downgraded, or abandoned to prevent competition of any type.
Anyway I think the only decent sized new rail freight project proposed is DM&E’s Powder River Basin access line, at around 280miles new track, 560 rehabilitated track.
As I said before, the rest is usually restoration of previous freight lines, of small scale (e.g. Homer City Power Plant access in Pennsylvania)
I have a railroad being laid outside my bedroom window as we speak. Its pretty damn annoying.
I know I’ve read in passing in the WSJ that a number of freight lines (IIRC, Canadian National especially) are spending lots of money restoring old track that they’d removed from service in the 80s & 90s.
Another freight project that’s forever up for debate here in NY is a line across NY harbor to connect Brooklyn with New Jersey.
There are also two significant passenger tunnel proposals: East Side Access, which would connect the Long Island Rail Road to Grand Central and, I believe, a terminal at 59th Street; and a second pair of tubes to serve Penn Station from New Jersey.
The London-Paris high speed link was recently completed, with similar sections to be built over the next decade.
Spain has built and continues to build high speed trains.
http://edition.cnn.com/2003/WORLD/europe/10/12/biz.trav.spain.train.ap/
http://www.alleuroperail.com/ave/ave-1st-class.htm
Germany and Italy are also building new high speed lines. The high speed rail network is so extensive in France that few people bother to travel by internal flights. Air France ceased flying to Brussels a couple of years ago because most people travelled on the high speed line between the two capitals.
I have heard it said that when Germany completes its new rail network it would like to see the end to all its internal flights so as to reduce the overcrowding in the air routes over Europe.
Will any long-distance high-speed rail systems ever be built in the U.S.? Have any systems even been proposed here?
Side note/hijack: The Discovery Channel ran an “Extreme Engineering” show this past Sunday explaining what would be involved to construct a trans-Altantic underwater rail tunnel between The U.S. and Europe. The estimated cost of such a project was $12 trillion. I doubt I’ll ever see it built in my lifetime, though.
Further hijiack: Why would you want to do that anyway? Even assuming you’d have a super-train going at 500 km/h, it would still take you twice the time than in an airplane. I don’t want to even imagine the maintenance costs on that thing.
It would make for a cheesy disaster movie, though.
The only thing that might make sense in that context is a near-ballistic subway running through evacuated tubes, like in the old science-fiction move Genesis II, but I’m not sure whether even that wouldn’t be beat by vehicles making suborbital hops.
It would make sense (in some limited fashion) for a freight railroad, as the trains would be able to haul near shipload amounts (well, a series of trains pulling 15Kt+ loads) at reasonable speeds (100Km/hr+ or so) - crew change points for hour of service would necessitate a passenger sleeper car in the consists near the locomotives (image the drawbar strain on that).
For passenger rail (which is the real target), I kinda agree that it would be impractical. Indeed, the far more practical (in engineering terms) Trans-Bering Strait crossing would still be uneconomical passenger wise.(however, I believe a line paralleling the Alaska Highway to Fairbanks, there to join with the Alaska RR).
Any number have been proposed - for Texas, for California, for Chicagoland, for the Northeast Corridor, and I think even for the Northwest (Portland-Vancouver, BC). My guess is that only the Northeast would be even remotely economically viable, because it’s the only part of the country that has European-style density. For all their well-documented problems, road & air have been pretty effective in the rest of the country - they’re more flexible than rail, and they’ve required lower up-front investment. In the Northeast, the problem has been not only cost, but right-of-way, which is why we’re saddled with Acela trains running on 100-year-old lines.
I’d love to see more rail lines, and we may have a greater chance of getting them as people start to recognize the substantial costs of our road and air systems. But I wouldn’t count on that realization coming very quickly.
There’s a plan to build a high-speed rail system in Florida. It might never happen – the Jeb Bush administration and several private forces are doing everything they can to kill the project, even though voters approved in a referendum. And nobody’s clear on where the funding would come from (we’re talking about a state project). On the other hand, Disney is entirely behind the project now that the High Speed Rail Authority has agreed to put a stop at Walt Disney World (instead of the Orange County Convention Center), and Disney has a lot of clout in this state, so who knows?
See:
http://www.davidpinero.com/rail/hsr.cfm
http://www.floridahighspeedrail.org/
http://news.tbo.com/news/MGAB32ZTAMD.html
http://www.baynews9.com/site/NewsStory.cfm?storyid=26770
http://www.theledger.com/apps/pbcs.dll/article?AID=/20031027/NEWS/31027002/1039
http://www.globeandmail.com/servlet/story/RTGAM.20031027.wbombardier27/BNStory/Business/
http://www.bombardier.com/fluor/
http://www.sptimes.com/2003/10/28/State/Disney_depot_in_train.shtml
There is new rail construction in the USA. See the Dakota, Minnesota, and Eastern Railroad map at
http://www.dmerail.com/PRB/Projectoverview%20Map.htm
Huge opposition in Rochester, MN about the upgrade and expansion. Map shows new rail planned for SD and WY tapping the coal fields there and moving coal east to the Mississippi River.