The prominent Electric Railway sign above Derby Castle will start being removed from next week.
Government says the supporting frame for it has become corroded and the decision has been made to take it down for safety reasons ahead of winter.
The current structure has been in place since 1993 when the MER celebrated its centenary.
The operation will involve the use of two large cranes - one situated in the Manx Electric Railway yard and another on Hague Crescent in Onchan
Officials are planning to find a replacement for it which, they say, will be installed to coincide with the start of the 2021 railway season next spring.