Research ready to use
The role of solar reflective paints on GB rolling stock | Heavier loads to make rail freight more efficient and reduce emissions | Higher speeds for freight trains | Review of the curving rules defined in the Track System Requirements
Research explored the potential contribution of solar reflective coatings to maintaining passenger comfort during hot weather.
Extreme summer temperatures are becoming more prevalent in Great Britain, leading to heat discomfort for passengers as air conditioning systems become overwhelmed.
Solar reflective paints are widely used in sunnier countries. In India, for example, trials have shown ambient temperature reductions of 15%. On the GB rail network, similar materials have been used in lineside cabinets and rail webs, and more recently they’ve been used on London Underground rolling stock.
This project investigated the technical considerations and business cases for introducing solar reflective coatings on GB mainline carriages, in particular on vehicle roofs. It aimed to establish how far interior carriage temperatures can be reduced and the potential to draw less power for air conditioning systems.
Because the solar reflective performance of current GB coating systems has not been measured, the benefits of introducing highly solar reflective materials—which come in all colours—could only be estimated. While a theoretical reduction in saloon temperatures could be as high as 7–10°C, much depends on the current paint. For example, the reduction in solar gain of repainting a dark grey roof white is expected to be 2.5–5 times larger than replacing a standard white paint with a specialist solar reflective alternative.
There is minimal energy-saving value from using a more solar reflective paint due to the low number of hot days in an average GB summer. However, in terms of customer experience, there is significant value in reducing the saloon temperatures during heatwaves. Improved passenger comfort at these peak moments is the primary value that coatings with higher solar reflective performance can provide.
The model also allows users to calculate the potential reductions in emissions, including carbon of alternative freight modes.
To download the full report, go to rssb.co.uk/research-catalogue and search for T1310.
If you are looking to trial solar reflective paint on in-service trains, we would be happy to support and work with you to confirm the benefits of specialist coatings. Contact Paul Gray, Professional Lead, Engineering:
Paul.Gray@rssb.co.uk
Research findings will allow greater tonnage to be carried using existing locomotives.
After unlocking longer freight formations by looking at limits driven by the strength of couplers, our freight-focused Research Programme turned its attention to maximum tonnage (trailing load). The weight a freight train can haul under current regulations is partly based on the power of the locomotive. By re-examining the engineering principles behind how those limits are calculated, we have unlocked the potential for existing locomotives to haul heavier loads.
The methodology for calculating trailing load limit was first standardised by the British Railways Board, with technical details dating back to 1969. The methodology and assumptions underpinning it were derived for locomotives on the network at the time and have remained largely unchanged.
With locomotive capabilities improving over the years, there was a clear opportunity to revise the methodology—not least because improvements to locomotives’ traction control mean that more can be hauled with the same amount of power. We redefined the methodology for calculating trailing load limits to accommodate these advances in locomotive capabilities and looked at a wider range of locomotive classes.
The work also considered the impact on timetabling of heavier trains, producing a calculator to determine the maximum load that will not increase journey times.
Operators can now take advantage of these higher limits on a case-by-case basis using an agreed process with Network Rail known as Service Plan Review. RSSB continues to work with Network Rail to use the calculator to update values in the Freight Train Loads Book, so all operators can automatically take advantage of the higher limits.
RSSB’s research projects are bringing modern thinking and analysis to age-old issues and will enable more goods to be hauled by train without needing investment in new infrastructure or rolling stock.
Read more about the research at rssb.co.uk/research-catalogue (search for T1302).
We are working with freight operators to take early advantage of these new values and applying the findings from research into freight coupler strength (T1256). To find out more and get involved, contact Aaron Barrett, Lead Research Analyst:
Aaron.Barrett@rssb.co.uk
Calculating real-world braking performance could unlock higher speeds for freight trains on parts of the network.
Maximum allowable speeds for freight trains are partly governed by assumed braking capabilities. The assumed braking rates are conservative to ensure that freight trains with the worst capabilities are accommodated and can safely stop.
It is known that many freight trains have better braking than is assumed, meaning these services may be limited to speeds below what could safely be allowed. Slowing down has many negative impacts for freight operators and the wider network, including higher costs, decreased path availability, and reduced overall network capacity.
Using braking data from real-world freight locomotives and wagons, this research has demonstrated that on parts of the network where freight speeds are limited due to signalling distances, higher speeds could be unlocked by applying an Enhanced Freight (EF) speed differential.
This method relies on accurately defining a train’s ‘lambda’ value, which is also used in the European Train Control System to characterise the true braking capabilities of freight trains. RSSB is now working with industry to assess where implementing such EF speed differentials will bring capacity and performance benefits.
Read more about the research at rssb.co.uk/research-catalogue (search for T1266).
We are looking to work with freight operators willing to be early adopters, taking advantage of EF speed differentials as part of the implementation of the findings. To find out more, contact Aaron Barrett, Lead Research Analyst:
We have looked at the justification for existing rules, their impact on safety, wear, and passenger comfort, and the case for making a change.
The existing track design rules define parameters for curves, ensuring the safe and comfortable operation of rail vehicles. These rules were based on empirical evidence and have remained largely unchanged for many years. There are an increasing number of challenges and deviations to the curving rules. For example, in some cases, the level of cant on the network can exceed the requirements defined in Railway Group Standard GCRT5021 - Track System Requirements but has been shown to have satisfactory dynamic performance and pose no significant hazards.
A review of the rules and processes in track design that lead to a more flexible approach could, under some conditions on the network, remove speed constraints and reduce the need for a costly redesign of track.
To determine whether all the current requirements are essential to operational safety, a number of case studies have been carried out using vehicle dynamic simulations to evaluate specific requirements:
cant and cant deficiency limits
cant in tight radius curves
virtual transitions
rate of change of cant and cant deficiency
vertical curves
reverse curves.
The project has provided evidence to support potential future changes to standards and can be used to inform the relaxation of certain requirements based on site-specific assessment and/or specific track construction.
Read more about the research at rssb.co.uk/research-catalogue (search for COF-UOH-73).
To discuss the research, contact Andrew Gleeson, Senior Partnership and Research Grant Manager:
Andrew.Gleeson@rssb.co.uk
