Author: Ben Mitchell -

One month into my second placement and I’ve now got my head around what my new team does and, after a slow start, finally have some work to sink my teeth into. My new team is part of the Capital Programme’s Directorate. The projects this directorate are involved with are to renew ageing assets, rebuild some of the network’s most congested stations, increase capacity on the busiest lines and to also replace obsolete systems with the latest technology. These are all critical to supporting the continued growth and regeneration of London.

The works already completed range from upgrading the signalling on the Jubilee line, increasing capacity by a third by allowing trains to run much closer together, to introducing Wi-Fi across the network.

The team I have been placed in is the Integrated Stations Programme, working with the vents and cooling systems in place in the underground. With the capacity of the network on the rise there is an ever increasing amount of heat being produced by the system, whether that be from the regenerative breaking of the trains or the commuters themselves. It is therefore necessary to constantly upgrade and replace the fans and condensers that provide comfort cooling, not quite air conditioning, to the stations.

The work I have been involved in so far in its most basic form is pressure drop calculations. In order to determine what fan is required for installation you must first find the Index Route. This is the route of greatest resistance within the system where the pressure drop will be greatest. Typically, but not in all circumstances, this will be the longest route within the system. Once this route has been calculated you are able to calculate the size of the fan and the flow rate it is required to produce in order to ensure there is sufficient air flow at the extremes of the cooling system.

Alongside this I have been introduced to the Microstation, a CAD programme used to model the position of the vents and grilles by overlaying them above the floor plan of the station. By working from the CAD files and copies of the original installation drawings I created a Grille Schedule. As a new set of standards have recently been introduced the required flow rates for the various rooms within the station, such as ticket offices, mess rooms, or toilets, has changed, and it is therefore necessary to determine what the new required flow rate is and from this source an appropriate grille to be installed in the update.

As I am now approaching 6 months with TFL towards the end of March I had my mid-year probation review a couple of weeks back. This is part of the P&D (Progress & Development) process that everyone at TFL goes through and it involves a sit-down with the Scheme Advisor, personal mentor and sponsor to discuss your time so far with the company and assess your progress towards the objectives set at the beginning of the placement.  As you might imagine this tends to be more of a formality as I have regularly been meeting with all 3 over the course of the placement but it will be very useful should I decide to return for the grad-scheme in future.

Posted in: Department of Mechanical Engineering, Engineering placements, Undergraduate


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  • Great blog. Big fan. Keep up the hard work!