Introduction to NA25

The new, ”interactive”, self curing, silent railway track system

(Noise/ screaming is a symptom, expressing bad condition, rapid detoriation – ”health is silent”.)

NA25 is new, innovative, unique – still basically (and at first sight) a ”standard” railway track. ”Secrets” are: high quality in every detail, without any compromise, including new, patented rail fastening. Investing in NA25 is an investment in high quality – for improved wheel/track alignment and lower costs. Earlier, before the new NA25, only options for restoring dynamic alignment (and silence) was lower speed alt. more or less regular synthetic/destroying adjustments- grinding, lifting/tamping etc.

Parameters of high quality NA25 are optimal so damages under traffic are reduced to minimal and such that when occurring they are to be in fact self cured – short pitch corrugations and basically same when ”hung” sleepers appear etc. (system is with ”intelligence”). NA25 is a new option to be evaluated as an interesting alternative at any location today suffering from:

  • slip and wear (corrugations on rail and wheels),
  • lack of acceleration and braking capacities,
  • high costs for long tunnels, viaducts and ramps (shorter do with NA25 thanks to steeper sloping allowed),
  • airborne noise radiated from rail and wheel (wheel/rail noise is strictly related bad alignment.),
  • ground borne vibrations and corresponding potential risks for eventual total structure collapse (e.g. at areas supported by stiff structure pilings and these are not allowed for pulsating, dynamic forces),
  • complicated, expensive ground conditions or elsewhere where slim lightweight design is preferred etc.

Graphs (top) illustrate difference between standard (ST) track (right top) and NA 25 (NA) track (left top). As well amplitude (A) of dynamic forces and max. static load (P) per sleeper/wheel load are reduced. Also amplitude is less varying over sleeper span. Thereby contact is maintained (alignment wheel/rail) also when amplitude is at max. on sleeper (min. force is maintained > 0)

Fig. below is illustrating supreme even load distribution with NA 25 high quality track. Fig. is for 2-axial wagon on S49 rail, sleeper track. 3 nos. ”centric” sleepers evenly absorb and distribute 70 % of each axial load over ca 2 m track length. Balance is distributed linear as on fig. over total ca 5 m track length. Sleeper track NA 25 thereby exhibits advantages of a slab track, maintaining do of a sleeper track. ”Small” closely centred NA25 sleepers tend to cooperate and with any single of those out of order (high) tends to be pressed down under traffic so nominal, ideal, even load distribution is restored (self curing). (Compare how ”big ” sleepers with large support area/sleeper call for synthetic – tamping – at more frequent intervals.)

This introduction is very short. For further information about interesting details, quotations etc. contact producer.

Investing in high quality

NA25 shall be easy to make

Being aware of existing problems and costs on such locations avoided by investing in high quality NA25 – decision in favour of NA25 shall be easy to make. Why then NA25 and not other fellow concepts also claiming high quality?

Please read further: NA25 is in standard and by concept providing what has been requested but has been regarded ”mission impossible”. As well isolating as damping (simultaneously) is one new, unique advantage with NA25. Still basically standard track technology is used. Any high quality track (as NA25) – shall compared with older do standard track improve and maintain:

  • distribution of wheel/axial loads along rail good, for maintained min. force on each support,
  • amplitude of pulsating forces reduced, all the way – on wheel, rail, support structure etc.,
  • energy induced upon system reduced to minimum (less energy wasted),
  • hysteresis, by safe contact damping, good all the way from each individual ballast particle to wheel/rail area (loaded or unloaded track),
  • resonance’s (natural vibration) freq. as few as possible in ”problem” area (e.g. ”well known” rail pinpin freq. is transferred to higher freq. area and there also dampened.


a) any standard rail – UIC60 etc. and known techniques for construction and maintenance allowed for etc.

b) NA25 constitutes PW (permanent way). Destroying/disturbing ”maintenance” – grinding, tamping – is reduced to minimum.

c) NA25 allows for construction/maintenance tamping without damaging (crushing) of ballast stones.

d) NA25 high quality track system is self-curing as: Speed dependant rail corrugation, caused by interference (resonance) at rail ”pinpin” frequency, is extremely ”short pitched” and thereby corrugation is in fact suppressed under mixed traffic. Hung sleepers are also by self curing aligned to neighbour higher, supported fellow sleepers as these simply are suppressed/aligned when hit by abnormal higher loads caused by hung sleepers (not distributing their complete, nominal load).

e) dynamic alignment (receptance) good – less total max forces and less amplitude of forces.

f) safe – track movements minimal, temperature forces safely and evenly distributed. Stabile consolidated, stabile tracked maintained for longer periods – less disturbing/risky maintenance tamping requested, acceleration/braking capacity improved,

g) costs for tunnels minimized, steeper sloping gradients allowed.

h) rail/wheel noise minimal.

h) improved riding comfort: improved track alignment, less demand for speed limits.

i) higher net axial/wheel loads and speed allowed, improved and safer distribution of axial load, dynamic, system related load less.

j) less wear on track and rolling material.

k) NA25 is versatile, flexible – which among others means – NA25 track is with option for high speed air proof function (aerodynamic, low air friction), less risks for loose stones etc.

k) opens for new design of future wagons/boogies, safer, less energy wasting, silent.