Mailgram Telegram July 1942 False Clear Signal Maintenance Railroad Trains. The Mailgram sent on July 29, 1942 describes how a false clear signal, just west of Columbus, Nebraska was reported. The Telegram sent on July 27, 1942 refers to various rail accidents and collisions. Mailgram Telegram July 1942 False Clear Signal Maintenance Railroad Trains please see the pictures for condition.