First Rail like-for-like passenger revenue growth was 5.5% for our portfolio excluding SWR (which was only part of the division for four weeks of the prior period). Industry conditions remain very challenging with macroeconomic uncertainty, infrastructure upgrade works across our networks and the industrial action in SWR all affecting our franchise performance levels. Like-for-like passenger volumes decreased by 1.9% in the period, reflecting the transfer of certain of GWR's Thames Valley flows to Transport for London in May 2018. Recent volume trends also reflect changing work patterns resulting in a shift away from season tickets towards pay-as-you-go tickets, an effect which is exaggerated by the way these journeys are recorded in industry volume statistics. Divisional revenues increased to £1,224.2m (H1 2017: £677.4m), with a full period of operation for our SWR franchise and the planned transition of GWR from premium to subsidy in period due to the cost of new rolling stock. Adjusted operating profit was £29.3m (H1 2017: £31.1m), with the margin reducing as expected, to 2.4% (H1 2017: 4.6%).
Divisional profitability was driven by GWR, where customers are seeing more capacity and services as a result of the introduction of new trains. Although electrification works by Network Rail have proved to be slower than originally planned which has led to issues with training drivers for the new trains, we are now introducing Hitachi Intercity Express Trains across the network. We also continue to work with our industry partners to reflect the impact of these delays in the level of our franchise commitments and model. Our rail franchises cover a period during which there is significant change (major infrastructure work, electrification and resignalling, and introduction of new trains). These changes require careful planning, management and negotiation with industry partners, in particular where delays can impact the delivery of franchise assumptions. Failure to manage these risks adequately could result in financial and reputational impacts to the Group. After the period end we have also begun the process of transferring the operational aspects of Heathrow Express to GWR, as previously announced.
SWR performance levels remain challenging, reflecting infrastructure issues that began before we took over the franchise. An independent review chaired by Sir Michael Holden has set out a blueprint for Network Rail and SWR to return service to levels that our customers expect. As part of these plans, we are investing £5m in performance improvements and next year the first of our £895m new suburban fleet will arrive. We are also introducing more convenient ticketing options such as flexible and auto-renewing season tickets. Our SWR customers have also faced considerable disruption to their journeys due to RMT’s ongoing industrial action, which we view as completely unnecessary since no employees will lose their job. In fact we have guaranteed that a guard with safety critical competencies will be rostered on every train, and, given our plans envisage running more services, SWR will want more guards in future not fewer. SWR are focused on delivering a resolution of the industrial dispute in the interests of our passengers.
TPE delivered growth and financial results in line with our revised expectations. Our plans to increase capacity on the network by more than 80% and create a true intercity railway for the North continue with new trains to be introduced in the next few months. Franchise performance at TPE was significantly affected by the timetable changes in May, as challenges experienced by other operators in the region had a knock-on effect on TPE’s punctuality statistics.
Meanwhile our open access operator Hull Trains is performing in line with our expectations despite some challenges due to fleet unavailability. New trains are due to be brought into the fleet next year.
In July, a national rail industry decision was announced to defer this winter’s timetable changes for several train operators, including GWR, SWR and TPE. This deferral is a significant and an unforeseen change, which means we cannot deliver some additional services and other passenger benefits as originally scheduled. In accordance with current franchise agreements, we are engaged in discussions with the DfT to work through potential commercial and contractual amendments, a process that is ongoing. The SWR franchise agreement includes a mechanism to share the Central London Employment (CLE) revenue risk with the DFT. There is uncertainty regarding the outcomes of this mechanism over the remaining franchise term, which has the potential to significantly impact the profitability of the franchise. We are reviewing the effectiveness of this mechanism and whether it is functioning as originally intended by both parties.
As a result of ongoing industry conditions and the tough operational environment our portfolio is experiencing, we continue to expect a smaller year-on-year adjusted operating profit contribution from Rail.