The Alco FA-1's are really great looking and smooth-running locomotives.  I have them in Rock Island, Great Northern, and New York Central road names. 

Western Roads Streamliners
http://www.youtube.com/watch?v=I8bwdcz6Y68

Western Roads Heavyweights
http://www.youtube.com/watch?v=QTyYb0xq0Po

Eastern Roads Steam Heavyweights
http://www.youtube.com/watch?v=oo1LLDBXrE0

Eastern Roads Diesel Heavyweights
http://www.youtube.com/watch?v=TXxPDKE1geQ

York Trains has a Facebook page, but the last entry was from 2012:

https://www.facebook.com/york.trains

York Trains, of Highland, Indiana, went out of business a number of years ago (as far as I can tell, after doing an address search), but for some reason, their old web site from 2005 is still on the web.  If you don't happen to have any Williams Trains catalog from that time, it might be historically interesting to see the very large number of road names that were once available for Williams passenger cars and locomotives.

http://www.yorktrains.com

I bought a used set of Williams Erie Alco PA-1's and a set of Erie 60' Madison cars off eBay, and the York Trains sales receipt was still inside the box.

A passenger car that has a portion of the car used for baggage is called a combine, sometimes called a "combo."  Observation cars don't always have domes; only streamliners do (not heavyweights); the California Zephyr was famous for having a dome observation car.

Try this dealer (scroll about half way down the page):

http://www.alleghenyscale.com/o%20scale/O%20Scale%20General%20Decals%20-%20Champ.htm

The tips about lubricating the center roller are very helpful information.  I own several sets of 1970's/early 80's Madison passenger sets with the old style free-spinning wheels and center pickup rollers that are mounted on a plastic bracket that snaps onto two of the three axles.  The Southern Pacific Madison cars are so hard to pull that my MTH RailKing Daylight 4-8-4 had trouble pulling them (the traction tires might need replacing), so I used a Williams SP Daylight GP9 (a stronger puller).

My local hobby shop sells fast angle wheel sets, but these are not compatible with the center roller design that snaps onto two of the axles of the 6-wheel trucks, because they require a static (not rolling) axle.

Well, I managed to collect 8 Williams California Zephyr aluminum passenger cars (only one dome car, though), and a Weaver dining car, as well as Burlington, Western Pacific, and Rio Grande diesels.  See them running here.

https://www.youtube.com/watch?v=Wk0t_kP2538

When was the last run of Williams aluminum 60' California Zephyr passenger cars?  It took almost a year of searching, but I acquired a used set at a good price through eBay that must have been made during the 1970s.  As far as I can tell, it is still a popular set, and hard to find in O gauge. 

The electronic board connected to the loudspeaker inside the tender is the Tru-Blast whistle sound board controller.  The reversing board is inside the boiler of the steam locomotive wired to the motor.

WBB only makes the 4-car sets of Madison heavyweights in the Erie road name, in the two-tone green paint scheme.  They are selling at Trainworld for about $100.

http://shop.bachmanntrains.com/images/WBB/43454.jpg

The motor has seized up on the Hudson.  I will try to get it repaired.

New Madison passenger trucks from Bachmann run about $20 each.

The 4-car set on eBay is of more recent Williams (pre-Bachmann vintage), with red boxes:
http://www.ebay.com/itm/Williams-modern-O-Burlington-60-Madison-M1033-four-car-set-sealed-468390-/151187989022

The 2 add-on cars have silver boxes marked "Crown Edition," which are older
http://www.ebay.com/itm/Williams-modern-O-Burlington-60-Madison-M1033CC-two-car-add-on-sealed-468391-/161173795807

The Burlington Madison cars had an olive green paint scheme.  These photos are from a different auction that has ended:

http://p2.la-img.com/227/48412/22401784_1_l.jpg

I have over half a dozen Williams Madison passenger cars sets, of all vintages.  Only the 1970's versions have plastic trucks with unflanged plastic "blind" center wheels and non-centering plastic couplers.   Metal trucks with three sets of fast-angled wheels with metal self-centering couplers became standard features on Williams Madison cars from the mid-80's and later.  These Burlington cars should fit the latter description.

A Google search of "Williams 468390" comes up with a hit for an eBay auction item; they are a 4-car set of 60' Burlington Madisons cars marked "Crown Edition."   If I recall correctly, "Crown Edition" would make these cars of mid-1980's vintage.

http://www.ebay.com/itm/Williams-modern-O-Burlington-60-Madison-M1033-four-car-set-sealed-468390-/151187989022

The 2-car add-on set may be found here:

http://www.ebay.com/itm/Williams-modern-O-Burlington-60-Madison-M1033CC-two-car-add-on-sealed-468391-/161173795807