Related Clues:

• Chicago sights
• Ernie of the P.G.A.
• Overhead trains
• N.Y.C. sights beginning in the 1870's
• '... or ___!'
• Woods rival
• Urban trains, for short
• Level ends?
• See 52-Across
• The six of ''Little Nellie Kelly''
• Hollow center?
• Cousins of monorails
• Tiger's rival Ernie
• Trains overhead
• Urban transportation