The city right beneath the emperor's carriage was called the capital.
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辇 was first a cart pulled by men, then specifically the emperor's carriage. From this comes 辇下 ('under the imperial carriage', meaning the capital) and 京辇 ('the capital').
车 is the vehicle radical at the bottom, a silhouette of a cart seen from above. Men above plus a cart below say it plainly: a carriage drawn by people.
The top is two 夫 (men) side by side, picturing laborers walking abreast to pull the cart by hand. This is what distinguishes a 辇 from a horse-drawn carriage.