high temperature, high heat

to emit white heat / (figuratively) to become heated (impassioned)

white heat / (figuratively) becoming heated (impassioned)

(archaic) iron / (figuratively) something extremely strong

iron

iron, the metal and the metallic chemical element / (more generally) steel / short for 鉄砲 (teppō, literally “cannon”, but in this case, refers to the poisonous fugu blowfish or dishes made from it)

incandescent light bulb

iron pipe

(shogi) iron general (a piece used in dai shogi and larger shogi variants)

(slang) fan of the sounds related to trains and rail transport (whistles, jingles, announcements, etc.)