The Blinking Signal with Bell No. 155 was produced between 1955 and 1957. This signal uses the warning lights cross beam from the No. 154 Highway Signal, and the cross buck that was on the No. 140 Banjo Signal. Other than these parts, all of the remaining construction was new for this accessory.
This signal is a clever adaptation of Lionel’s venerable vibrator that had three impeller vanes attached. When activated by a No. 145C Track Contactor this signal’s vibrator’s three vanes would rotate. One vane triggered the bell and the other two caused the lights to flash alternately by causing leaf contacts to complete the circuit. The rotation of the vanes was caused by an adhesive and rubber washer with prongs similar to what was used on the No. 3520 Searchlight Car (Adhesive Washer Part No. 3520-42) (Rubber Washer Part No. 3520-16). The driving "fingers" on the rubber washer eventually wear down and when this happens the signal will not operate. Replacement parts are available. The Lionel Service Manual states that a graphite lubricant should be used on the cup that the rubber washer rides on and that any type of oil or grease lubricant should NEVER be used.
In 1956 Lionel would replace the leaf contact mechanism (Part No. 155-40) with a coil spring assembly (Part No. 155-70) that offered a more reliable operation. The Lionel Service Manual for 1956 advised not to replace these individual parts, but to instead replace the whole mechanism. In addition, Lionel would add rubber grommets to the base. Lack of these grommets in the base is the simplest way to distinguish a 1955 issue.
Lionel had the same problem with the WHITE color of the base turning a CREAM color, or an even darker shade of CARAMEL that happened to other items that they produced during this period like the No. 57 AEC Vulcan Switcher and the No. 6376 Circus Car. However, among these similarly afflicted items is often found some that have not turned color indicating that at least two different types of WHITE plastic was used during their production.