Quotes :

"The TOC Operating Cost Module background documentation sets out the processes and methodology underlying NMF modelling. This module includes the train operating costs as well as the ICM (Infrastructure Cost Model), but does not detail commercially confidential information of train operators." (link below.)
http://www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/nmftoccostmoduleb1.pdf

"The Financials and Physicals (F&P) Document details how NMF collates information from all calculation modules, presenting the user with all the key financial and operational diagnostics within the model. It also includes the baseline specification used in NMF as part of the HLOS process."
http://www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/nmffinancialsandph.pdf

"The NMF – Appraisal Background Documentation has been produced by Steer Davies Gleave and Delta Rail to detail the structure and working of the ‘Appraisal Module’ in NMF. This module calculates the Value for Money of rail schemes. Such calculations are based on NMF outputs (from other modules) and parameters/values and calculations consistent with WebTAG and STAG (Scottish Transport Appraisal Guidance)."
http://www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/nmfappraisabackgro.pdf