grammar - What is the role of あるいて?

駅からは歩いて十分ぐらいです。
It takes 10 minutes on foot from the station.

The confusing part is the 歩いて.
Is あるいて a noun? What is its role?

Answer

歩いて is the te-form of the verb 歩く, and means "on foot". Of course the te-form usually connects to another verb, but the te-form of some words (seem to) have idiomatic usage which can be used on its own. (As a native speaker I haven't learned Japanese grammar systematically, so I may be wrong...)

• もって3日だ。 (Someone can bare/survive) for three days at most.
  (This もって is the te-form of 持つ or 保つ in this sense, and used idiomatically to mean "even if one hangs on")


• まして let alone / not to mention


• 従って therefore

In the case of 歩いて, I think you can also think 行くと or 行けば is omitted after 歩いて (i.e., 歩いて行くと10分です).