Nick Wolter, Fraunhofer IFAM (see pinfa Newsletter n°105 FRPM 2019), presented the Mat4Rail project, developing innovative composite materials using polybenzoxazine (high performance, low density polymer), basalt fibre reinforcement and phosphorus PIN FRs. This combination offers low shrinkage and heat release on curing, high service temperature and good mechanical properties, with low weight. Appropriately selected P-FRs have the benefits of improving processing by decreasing viscosity and delaying or catalysing curing, do not deteriorate tensile strength, but can deteriorate interlaminar shear strength – showing the need to work on the fibre – plastic interface. The addition of basalt fibres to the polymer reduce heat release, smoke toxicity and smoke density. The P-FRs tested offer somewhat similar or poorer fire performance and worse smoke density and toxicity than neat polymer with basalt fibres, so further work is needed to find appropriate PIN FR packages. However, PIN FRs can be used in benzoxazine technology to obtain tailored processing properties facilitating market implementation of new high performance polymers.