[en] Four ¹³CO spectra having similar and asymmetrical shapes (blueshifted peaks) were observed with 30 kHz resolution toward TMC2 and L134N. A radiative transfer model of a symmetric cloud indicates that each cloud is contracting along the two observed lines of sight. Contraction onto a static core fits the observed ¹³CO and C¹⁸O lines slightly better than contraction with vproportionalr. The contraction speed approx.0.7 kms^-1 and velocity dispersion approx.0.3 kms^-1 are consistent with a 15 K cloud having a free-fall envelope and sonic turbulence