Can you confirm whether the following statement reflects The Planning Inspectorate's approach.
The Planning Inspectorate has advised that [Rail Central applicant Ashfield Land] should have regard to the emerging Roxhill proposals in terms of [Rail Central's] assessment and technical studies (i.e. for cumulative impact assessments) but that any examinations of two potential DCO applications coming forward will be separate.

Please see below a link to a recent Project Update Meeting between PINS and Rail Central (Ashfield Land) where this matter was discussed. For ease of reference I copy the text most relevant to your query as part of this email.
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“The Inspectorate noted that there had recently been proposals for a Strategic Rail Freight Interchange in very close proximity to the Rail Central site – The Inspectorate had received a Scoping Request for the proposed Northampton Gateway Scheme on 21 October 2016. The developer noted the proposals and confirmed that they would be including the project as part of their cumulative impact assessment. The Inspectorate considered it would be helpful if both developers could be as clear as possible in any consultation activity about the existence of the other to assist those who wish to provide consultation responses.
The Inspectorate confirmed that it had received queries about how the PA2008 regime would or could deal with a situation of two Nationally Significant Infrastructure Projects (NSIPs) of the same ‘type’ (i.e. Strategic Rail Freight Interchange) in very close proximity to each other.
Following submission and acceptance of a Nationally Significant Infrastructure Project (NSIP) application made in accordance with the Planning Act 2008 (PA2008), an Examining Authority (ExA) will be appointed to formally examine “the application”. The application seeks approval for the proposed development as identified in the accompanying plans. If made, a Development Consent Order cannot give permission for a wholly alternative site or a wholly different scheme to that which has been identified as the proposed development, or development site, within the DCO application.
The PA2008 does not explicitly provide for a situation whereby an ExA could be appointed to consider more than one application simultaneously (that is to effectively hold a joint examination of multiple applications) although this is not explicitly precluded. Notwithstanding the legality of such an approach, in practical terms the scale and complexity of the issues in examining two separate and independent NSIP applications within a 6 month examination timetable could have implications for achieving legally robust and distinct decisions as implied by PA2008. Furthermore, presumably such an approach would require separate applications to be submitted on very similar timescales and would need the agreement of both applicants.
However, aside from the legislative and logistical issues of an approach to examining two applications together, if a project requires an Environmental Impact Assessment (EIA) to be submitted as part of the application, the EIA Regulations necessitate that the applicant undertakes an assessment of cumulative effects, and considers alternatives to the proposed development. The assessment of cumulative effects would take into account other reasonably foreseeable schemes including any other relevant NSIPs. Given the scale of the proposed development for an NSIP it is highly likely that an EIA/ES would be required. More information on cumulative effects assessment including a proposed methodology can be found in Planning Inspectorate Advice Note 17. It is therefore safe to assume that the decision maker would be equipped with an assessment of the likely cumulative effects associated with both schemes including if they were both operational. The developer confirmed that they would be undertaking a cumulative assessment which would include the Northampton Gateway Strategic Rail Freight Interchange project.
When making a decision on whether or not to grant consent for an NSIP, the Secretary of State will have regard to any important and relevant matter; as will the Inspector(s) appointed to examine an application and report to the Secretary of State. The impact of a proposal on existing uses and its compatibility with other developments is a matter that could be raised in submissions and could be capable of being relevant and important.”