Ua kom tiav cov pa tawm yog cov khoom ncua kev kawm uas tsim los rau cov tsheb thauj khoom, cov tsheb thauj khoom thiab cov tsheb thauj neeg hnyav;lawv pab tus neeg tsav tsheb thiab cov khoom thauj tau tsawg kawg nkaus los ntawm cov xwm txheej tsis zoo ntawm txoj kev, khaws lub tsheb sib npaug thaum lub sijhawm thauj khoom, thiab ua kom txoj kev, cov khoom lag luam thiab cov neeg caij tsheb nyab xeeb nyob rau theem siab tshaj plaws los ntawm kev tsav tsheb sib npaug.
Ua kom tiav cov cua springs muab kev yooj yim ntawm kev siv rau cov tsheb thauj khoom thiab tsheb thauj khoom los ntawm kev ua haujlwm xws li kev muaj peev xwm txav tau yooj yim thiab hloov qhov siab hloov pauv kom tau raws li daim ntawv thov thaum lub sijhawm thauj khoom thiab tshem tawm.
Los ntawm kev sib npaug ntawm kev faib khoom nruab nrab ntawm axles thiab kev khaws cia ntawm qhov nruab nrab ntawm qhov loj, degradation ntawm txoj kev loj yog txo qis thiab cov nqi kho tsheb mus sij hawm ntev tsawg.
Nominal ua hauj lwm ntau yam, natural zaus qhov tseem ceeb thiab load peev xwm rau cov khoom sib txawv nrog rau qhov chaw ntawm kev siv.