A longer urban train could carry more passengers, but extending every platform is costly. The front-and-rear operating idea uses a train longer than its platforms while controlling where it stops and which doors open, so travelers can still reach the correct station safely.
One continuous twelve-car train serves six stations. At a rear-type stop, the rear portion aligns with the platform; at a front-type stop, the front portion does. Doors outside the platform stay closed, and passengers choose sections that can serve both their origin and destination. Each stop shows alignment, alighting, boarding, door closure, and departure. The key insight is operational rather than simply physical: a short platform can serve a longer vehicle if stopping positions and passenger placement are coordinated throughout the trip. That coordination is demanding, but it offers a way to increase train capacity without rebuilding every station to the full train length.
Bus bunching can begin with a very small delay. A bus that reaches a stop late finds more passengers waiting, spends longer boarding them, and falls farther behind. The following bus encounters fewer waiting passengers and catches up. The original even spacing can collapse into a pair of buses followed by a long gap.
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Widening a road may shorten car trips at first. But if some bus passengers respond by driving, bus ridership falls. A transit agency trying to balance its budget may then run fewer buses, making transit less attractive and sending still more travelers to cars.
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A trunk bus line can move people efficiently along a corridor, yet passengers living far from its stops may face a long walk at both ends of the trip. That access burden can make an otherwise fast line unattractive.
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