Temasek Laboratories is developing a tunable acoustic absorber to mitigate the noise from railways in Singapore. The company will develop a smart quiet barrier based on acoustic metasurface, metamaterial and tunable transparent material, which can be installed on both the barrier wall and the passing train such that noises generated can be absorbed quickly. In addition, the absorption spectrum of the smart quiet barrier can be tuned to target the main noise, for example, the rumble of a heavily loaded train, the pitch of a lightly loaded train, or the high pitch of a train changing tracks.