With reference to the reply to question 3558 on 10 November 2017 regarding incomplete train stations, (a) what number of contracting companies have gone into liquidation (i) in the (aa) 2015-16 and (bb) 2016-17 financial years and (ii) since 1 April 2017 to date, (b) what are the implications and cost implications of each project for (i) Prasa and (ii) his department and (c) what mechanisms, processes and procedures are in place to measure the sustainability of contracting companies when appointed and (d)(i) when were the mechanisms, processes and procedures introduced and (ii) what outcomes have been experienced as at the latest specified date for which information is available?