鉄鎖 is read as てっさ (tessa) and means iron chain.
てっさ
tessa
てっきん
reinforced concrete
てっせい
made of iron
てっぽう
gun
てっこう
iron and steel
てつじょうもう
(barbed) wire entanglements
てつどうもう
railroad network
てっぽうみず
flash flood
てっぺき
iron wall
てつどうあんぜんすいしんかいぎ
Railroad Safety Promotion Conference
てっきじだい
Iron Age
てつどうじこ
railroad accident
てつどうしせつ
railroad facility