Noviro
铁丝
Simplified 铁丝
Traditional 鐵絲
Pinyin tiě sī
Definition iron wire; subway enthusiast (abbr. for 地铁粉丝); railway enthusiast (abbr. for 铁路粉丝)
他是个铁丝，超爱地铁
Tā shì gè tiě sī, chāo ài dìtiě
He's a subway enthusiast, really loves the metro
You might also see
丝
sī
silk; thread-like thing; (cuisine) shreds or julienne strips; classifier: a trace (of smoke etc.), a tiny bit etc.
粉丝
fěn sī
bean vermicelli; mung bean starch noodles; cellophane noodles; fan; enthusiast for sb or sth (loanword from "fans")
丝毫
sī háo
the slightest amount or degree; a bit
丝绸
sī chóu
silk (cloth)
螺丝
luó sī
screw
丝带
sī dài
ribbon
钢丝
gāng sī
steel wire; tightrope
丝绒
sī róng
velvet