I bought a book of train tickets, but didn't use them all before they expired.
I purchased a book of rail tickets, but didn't get through them all before they were out of date.
ーI bought a book of train tickets, but didn't use them all before they expired.
「電車の回数券を買ったが、期限が切れる前に全部使わなかった」
a book of train tickets で「電車の回数券」
to expire で「（有効期限が）切れる」
ーI purchased a book of rail tickets, but didn't get through them all before they were out of date.
「電車の回数券を購入したが、期限が切れる前に全部使い終わらなかった」
a book of rail tickets で「電車の回数券」
to get through で「〜し終える」
out of date で「期限切れの・無効の」
ご参考まで！
カナダ 
