2.3鐵路選線鐵路選線railway location, approximate railway location,location of railway route selection平原地區(qū)選線location in plain region, plain location越嶺選線location of mountain line, location of line in mountain region, location over mountain山區(qū)河谷選線mountain and valley region location, location of line in mountain and valley region丘陵地段選線hilly land location, location of line on hilly land工程地質(zhì)選線engineering geologic location of line線間距distance between centers of tracks, midway between tracks車站分布distribution of stations方案比選scheme comparison, route alternative投資回收期repayment period of capital cost紙上定線paper location of line緩坡地段section of easy grade, section of gentle slope緊坡地段section of sufficient grade非緊坡地段section of unsufficient grade, section of inficient grade導向線leading line, alignment guiding line拔起高度，又稱“克服高度”height of lifting, lifting height, ascent of elevation橫斷面選線cross-section method of railway location, location with cross-section method, cross-section method for location of line展線extension of line, development of line, line development展線系數(shù)coefficient of extension line, coefficient of developed line套線overlapping line線路平面圖track plan, line plan線路縱斷面圖track profile, line profile站坪長度length of station site站坪坡度grade of station site控制區(qū)間control section, controlling section最小曲線半徑minimum radius of curve圓曲線circular curve單曲線simple curve緩和曲線transition curve, easement curve, spiral transition curve緩和曲線半徑變更率rate of easement curvature, rate of transition curve復曲線compound curve同向曲線curves of same sense，adjacent curves in one direction反向曲線reverse curve, curve of opposite sense夾直線intermediate straight line, tangent between curves坡度grade, gradient, slope人字坡double spur grade限制坡度ruling grade, limiting grade加力牽引坡度pusher grade, assisting grade最大坡度maximum grade臨界坡度critical grade長大坡道long steep grade, long heavy grade動力坡度momentum grade均衡坡度balanced grade有害地段harmful district無害地段harmless district變坡點point of gradient change, break in grade坡段grade section坡段長度length of grade section坡度差algebraic difference between adjacent gradients豎曲線vertical curve分坡平段level stretch between opposite sign gradient緩和坡度slight grade, flat grade, easy grade起動緩坡flat gradient for starting加速緩坡easy gradient for acceleration, accelerating grade坡度折減 compensation of gradient, gradient compensation, grade compensation曲線折減compensation of curve, curve compensation隧道坡度折減compensation of gradient in tunnel, compensation grade in tunnel繞行地段detouring section, round section換側(cè)，又稱“換邊”change side of double line容許應力設計法allowable stress design method破損階段設計法plastic stage design method極限狀態(tài)設計法limit state design method概率極限狀態(tài)設計法，又稱“可靠度設計法”probabilistic limit state design method地震系數(shù)法seismic coefficient method