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I believe that a Weaver Gold Edition brass locomotive offers the best value that can be found for its high quality.

And arguably one of the most beautiful brass O scale locomotives that Weaver Models built was the Gold Limited Edition Canadian Pacific Royal Hudson 4-6-4, offered by Weaver about 20 years ago, selling out then in short order. This is #306 of only 438 made. It was stored away when bought, and has never been run on track or gathered dust on a shelf, only coming out of its box for pictures. It is in perfect, new condition and still has factory lubricating oil present underneath. It features:
  • All brass body construction, both plate and cast
  • Constant voltage headlight
  • Operating smoke unit with on/off switch
  • Operating marker lights
  • Operating knuckle coupler
  • Detailed cab interior with engineer and fireman
  • Precision DC can motor
  • Runs on O-54 track
  • Sprung drivers
  • Operates with any AC transformer
  • QS-1 sound compatible
  • DCRU Reverse unit by QSI Solutions
  • Authentic cab number
  • 3-rail
  • 1/4 scale (1:48)
Only five of the universally-acclaimed Canadian Pacific Royal Hudson 4-6-4 locomotives survive today, with #2860 being the most famous. #2860 is still fully operational, occasionally pulling special passenger trains on the British Columbia Railway between Vancouver and Squamish, BC and it has made trips to Eastern Canada as well as to Los Angeles. The six drive wheels are 75" each in diameter, the steam pressure of the boiler is 275 psi, it holds 47,000 lbs of fuel and 12,000 gallons of water. Total weight is 659,000 lbs (299 tons), overall length is 90' 10". Its adhesive weight, which relates to the friction grip between the drive wheels and the rail, is an astounding 194,000 lbs.  #2860 was delivered new in 1940, being one of only five oil-burning Royal Hudson 4-6-4s that were built, and it is considered one of the most beautiful North American steam locomotives ever built, in design, streamlined shape, and paint colors.