The long-awaited report detailing where light rail could head beyond its existing Newcastle Interchange terminus was released by Transport Minister Andrew Constance on Friday after the Newcastle Herald made a freedom of information request to Transport for NSW.

Its release comes four-and-a-half years after the government committed to the study as part of a deal to gain upper house support to close the city's heavy rail line and more than a year after Mr Constance declared it was in its "final stages".

The 64-page document provides a summary of investigations into four potential light rail corridors from Newcastle Interchange to: John Hunter Hospital via Broadmeadow, Mayfield, Wallsend and Charlestown.

The hospital route was the only corridor to have a positive economic benefit, despite having the most expensive construction costs.

The report does not provide a breakdown of the economic assessment, but says the estimated capital cost of each route would be "between approximately $900 million to $1.5 billion".

"At a corridor level per kilometre of track, the Charlestown route is the least expensive, whilst the John Hunter and Broadmeadow route is most-costly," it says.

"However, assessing the total whole of life costs for each option including revenue, the preferred [hospital] option has the lowest net present cost."

The results of a multi-criteria analysis, including the economic assessment and travel demand, highlight there is "no urgent need for an immediate extension" and "several prerequisites" required to reach a benefit-cost ratio above 1.0.

"The John Hunter Hospital via Broadmeadow corridor is most suitable to become the next stage," the report concludes.

"However, the corridor assessment results, especially the economic assessments, highlight that there is no urgent need to extend. The underlying drivers for the project extension, the need for infill housing and precinct development, may not eventuate in the shorter term (less than 10 years).

"This is because the Newcastle city centre is still undergoing land use and precinct transformation ... and this transformation may still take several years to realise."

The corridor was found to offer "major opportunity to deliver place making and urban renewal" outcomes, support development precincts, and deliver housing close to employment hubs.

It also has the potential to "absorb a greater share" of Greater Newcastle's dwelling and population growth, and could help fast-track infill development capable of housing 14,146 people.

"The corridor meets multiple strategic planning and transport goals, it intersects major urban renewal and employment precincts and has lower impacts to the traffic network compared to other options," the report says.

"[It] supports the urgent need for public transport connectivity to the [hospital], and has the highest projected ridership, peak loadings and transport benefits."

The proposed alignment exits Newcastle Interchange onto Tudor Street, runs onto Belford Street through the "Nine Ways" intersection and over the existing rail overbridge in Broadmeadow.

That bridge would likely have to be rebuilt, the report suggests, or a dedicated light rail bridge constructed.

The alignment continues onto Lambton Road, across Turton Road into New Lambton and onto the narrow and rising Russell Road.

At Lookout Road, it turns left into the median north of the road and up to the entrance of the hospital.

The route curves right down towards the hospital's main building to a terminus.

The ambitious 6.65km line would have to traverse grades of up to 9% between Westcourt Road after New Lambton Public School and John Hunter Hospital.

The report described a line to the hospital as "constructible" but with "more challenges compared to other corridors, in particular the Charlestown and Wallsend corridor".

"The current alignment between New Lambton and [the hospital] has significant constructability issues, however, alignment optimisation could possibly mitigate or reduce the technical challenges with gradients," it said.

The report proposed a two-stage project for a hospital extension. Stage one would involve a line from Wickham to New Lambton.

A terminus for stage one could be near the Wests Leagues Club, but the report noted the staging point had a "challenging rail design due to the upward sloping vertical grade of Lambton Road and the downward sloping grade of the two lots".

Seven stops are proposed on the route at or near: Beaumont Street, Steel Street, Blackall Street, Hunter School of Performing Arts, Turton Road, Tauranga Road and John Hunter Hospital.

The report notes existing road reserves in "several places" of the route are "insufficient to accommodate both light rail and traffic" and "without significant widening, it may reduce road capacity at intersections".

Constraints include the potential impact on property to accommodate both light rail and traffic and the "potential closure of Russell Road and resulting vehicular traffic/property impacts".

The report does not say whether the closure of Russell Road to traffic would be temporary during construction or permanent.

An extension to the hospital would require an additional six trams to take the total fleet to 12, of which 10 would run on the entire line during peak periods.

The study suggested building a new depot to accommodate the entire fleet and redeveloping the existing facility in Wickham because it is already at capacity.

The journey between Wickham and the hospital would take 30 minutes.

The alignment of the 9.05-kilometre route to Wallsend exists Newcastle Interchange on Tudor Street, turns onto Parry Street and runs through the Selma Street intersection before running along Donald Street and Griffiths Road.

Trams would run primarily in the centre of those roads and would run through the roundabout at Thomas Street, Wallsend, before terminating at Cowper Street.

The 10-stop line would require seven new trams and would take 37 minutes.

The major constraints for the route include impacts on the road network and encountering stage five of the Newcastle Inner City Bypass.

The Charlestown alignment, an 8.67-kilometre extension featuring eight stops, exits the interchange onto Tudor Street, turns left and runs in the centre of Gordon Avenue through to City Road, where it shifts into the north verge after Alice Street.

It returns to the centre of City Road at the Brunker Road intersection and then continues to Charlestown, where the line would terminate near Frederick Street.

It would require seven new trams and is constrained by high grades and narrow roads.

The shorter Mayfield route is a five-stop alignment along Maitland Road with a terminus at Frith Street.

The five-kilometre line was considered to be "affordable and have moderate costs", but have "poor transport patronage outcomes" and "not provide a strong base for urban renewal and employment growth".

It would only require four additional trams.

The four routes examined were shortlisted from 18 corridors set out in a state government transit plan for Newcastle in late 2017.

While the business case summary report ultimately concludes there are "strategic merits" to extending the city's existing 2.7-kilometre line to John Hunter Hospital, it notes there are multiple requirements to improve the economic assessment results, including:

The report recommends implementing a dedicated bus corridor on the hospital route which "could be easily converted" if a light rail extension was to proceed.

It suggests such an investment would "deliver early community benefits, support Newcastle light rail and align with the NSW fast rail network including connections to Greater Newcastle".

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