Related Clues:

• Alternative to air
• Fulminate (against)
• Third ___ (track adjunct)
• Pedestrian safety feature
• Billiards cushion
• Post by the stairs
• Commuter line, perhaps
• Flight support?
• Grand Canyon addition
• Part of a billiard table
• Commuter's option
• Train travel
• Traveler's choice
• Protest loudly
• Banister attachment