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The Team

Our team


John Greenwood

Programme Manager


John joined Network Rail in 2014, following a long career in Defence where he was actively involved in the implementation of large scale technology and people change programmes.

John is responsible for maintaining a competence assurance service for all individuals who work on Network Rails infrastructure through the use of compliance systems and technology such as Sentinel.  His main focus is to ensure that the Sentinel system is maintained and operated to the highest standard for all its users whilst ensuring that the planned replacement exploits the very best and innovative technology available.

Millie East

Assistant Project Manager


Millie joined Network Rail in January 2006 as a Training Administrator at Woking Training Centre moving into the Sentinel team in April 2014. Millie graduated from the University of Southampton in 2006 with a B’Ed and apart from her time in teaching has spent her career in the Transport industry, working at Heathrow Airport before coming to Network Rail.

Millie’s main role is on the implementation side of Sentinel. Millie liaises with the routes/regions and supply chain to increase the usage of the Sentinel app as well as managing and reporting on the data provided by the app.


Nikki Cresswell

Sentinel Specialist (Operations)


Nikki joined Network Rail in 2010, fresh from one of our principle contractors where she was an active member of their electrical projects group involved in the planning and financial management of electrical installations and maintenance.

Nikki is responsible for keeping the database management and administration running smoothly on behalf of the Sentinel Operations team. She spends most of her time problem solving, process managing and engaging with our end users and stakeholders to help them get the most out of new Sentinel.

Stella Nikolaidi

Project Manager


Stella joined Network Rail in 2012 and has a breadth of experience in different areas of the business, from Procurement, Business Continuity and Planning & Regulations to Route Services.

She has more than a decade of Project Management experience working initially in the manufacturing industry where one of the most prestigious projects she managed was the steel supply for the HMS Royal Aircrafts Carriers.

Yasemin Agarwal

Business Analyst


Yasemin has recently joined Network rail after a long career in Public Transportation in South Yorkshire where she was actively involved with several IT & Business Change projects.

Yasemin is responsible for analysing business change needs, assessing the business impact of those changes, capturing, and documenting requirements and providing the definition of technology and process solutions that aligns with business requirements on Sentinel development projects.