Our Foundress blessed Mother Mariam Theressia started the Educational Apostolate to impart "Knowledge of God" the intention of mother was to uplift the morale of the families "building up into an intimate community of life and love" we still continue this mission inspired by her enlightened spirit. The ultimate aim of mother is not to produce robots or manufacturer machinery but to be get citizens with flesh and blood and with love for God.We strive for internal formation and liberation of human person, imbibing scientific and technical knowledge with spiritual values as well. We aim at achieving excellence in every aspect of educational activity spiritual, academic, cultural, social and physical. Thus on the request of the then Railway employees and with the blessings of them Bishop of Thrissur His excellency Late Mar George Alapatt, two renunciates came to the Palakkad mission to start a school at Olavakkode. We bow down with reverence and gratitude to Rev.Mother Isabel and Rev.Mother Josephine who acquiesced to the demands of the railway authorities for an English medium school for their children. Thus was born St.Thomas in 1961 as a nursery in a rented building.

From a non descript start we grew from strength to strength. With the able assistance of Major M.J.Kuriakose A.P.O in the railway Divisional Office 9 acres and 3 cents of land was bought to start the construction of a permanent building for the school. That was the beginning of a saga. 

The school was shifted and Rev.Sr.Dorothy took charge in 1963 Rev.Sr.Servia was installed formally as the head mistress and recognition and approval was granted by the government for LP school. There was no looking back since then , as there was a steady increase in students;so there arose  a need for more rooms and another new building was constructed. Rev.Sr.Lucy took over as the new headmistress. Here we cannot but pay our humble tribute and acknowledgement for the efforts and services of Sri. CM Devassia and Mr. Pius Joseph. In 1967 late Rev.Sr.Marianus took over as the headmistress. In her tenure from 1967 - 1979 recognition of the high school was accredited. The first batch of SSLC students passed out in March 1974. We recorded 100% pass and this achievement has been maintained till now. 

Determination and perseverance are the two pillars for success. Over the years we have won accolades gathering as many as we can in both curricular and extra curricular. Though catering to the lower and middle class families , we are proud to affirm that we stand shoulder to shoulder with those more privileged. 

The victorious March of St.Thomas has been steered by Stalwarts late Sr. Regi Paul who was the pilot of St.Thomas from 1982-1991. During her period computer classes were introduced and included in the curriculum. In 1991, Rev.Sr.Sila took over as the headmistress.  New buildings, facilities, an open air auditorium was constructed along with new administrative block. The introduction of higher secondary was initiated on 2001 and St.Thomas became a co-education higher secondary school in 2003. Her last year at St.Thomas saw a spree of ranks including first rank by Remya K after which the grading system was introduced.  

She was succeeded by late Rev.Sr.Ansa Paul in 2004 who added more feathers to the cap of St.Thomas with the introduction of Edusat center. 2009-2012 saw Rev.Sr.Manjula  at the helm. 2012 is an important land mark as we progressed into our 50th year. The golden jubilee year was celebrated in 2012 with Sr.Sila as the principal. The annual day was celebrated with much gaiety. The inauguration of school official web site, release of the jubilee magazine and the bestowal of the keys of the house constructed under the scheme "Sahapadikkoru veedu" were the highlights of the year. The school paid its tribute to the former principals and PTA presidents.