# Symbols

Symbols and their meaning for railway construction

| Meaning of the symbol | Unit |
---|---|---|

a | Vertex distance with vertical curve | m |

AA | Start of vertical curve | |

AE | End of vertical curve | m/s² |

a_{r} | Radial acceleration | m/s² |

a_{p} | Transverse acceleration | |

BA | Start of curve | |

BE | End of curve | |

BM | Centre of curve | |

BW | Change of radius | |

e | Distance between centres of lines | m |

f | Displacement of the track curve compared with the tangent with a transition curve | mm |

h_{f} | Versine | mm |

Δ h | Height difference | m |

l | Longitudinal gradient | ‰ |

k | Curvature of the track curve | |

l _{a} | Length of the connecting curve with peaks and troughs | m |

l _{b} | Length of the circular curve (length of curve) | m |

l _{g} | Length of an intermediate piece of track | m |

l _{n} | Usable track length (also known as the UL) | m |

l _{R} | Length of the superelevation ramp | m |

I _{RB} | Length of the superelevation ramp according to Bloss | m |

l _{RS} | Length of the S-shaped superelevation ramp | m |

l _{t} | Tangent length | m |

l _{ta} | Tangent length of the vertical curve | m |

l _{U} | Length of transition curve, straight curvature line | m |

l _{UB} | Length of transition curve according to Bloss | m |

l _{US} | Length of transition curve, S shaped curve | m |

l _{w} | Length of turnout | m |

ldSch | Last long sleeper | m |

max | Attachment for highest value | |

min | Attachment for lowest value | |

1 : m | Inclination of the superelevation ramp | |

1 : n | Inclination of the turnout tangent | |

N | Inclination | m |

HüNN | Height above normal zero | |

NW | Change in gradient | m |

oA | Without details of the vertical gradient radius | |

r | Curve radius | m |

r _{o} | Radius of the branch-track of the turnout shape | m |

r _{a} | Vertical gradient radius of the change in gradient | m |

r _{s} | Radius of the main line of a curved turnout | m |

r _{z} | Radius of the branch-track of a curved turnout | m |

reg | Attachment for basic value | |

RA | Start of ramp | |

reg | End of ramp | |

RM | Centre of ramp | |

s | Distance of the centres of the rail heads or line | mm; m |

S | Line gradient as specified by DIN | ‰ |

TS | Tangent intersection point | |

u | Superelevation of the outer rail | mm |

u _{o} | Equalising superelevation | mm |

u _{f} | Cant deficiency | mm |

u _{u} | Superelevation excess | mm |

UA | Start of transition curve | |

UE | End of transition curve | |

UM | Centre of transition curve | |

v _{e} | Design speed | km/h |

WA | Start of turnout | |

WE | End of turnout | |

WTS | Point of intersection of the turnout tangents | |

zul | Attachment for permissible value |