Based on the idea of SLoPS, a probing technique, self-loading decreasing rate train (SLDRT), is proposed. SLDRT measures the available bandwidth by using a single decreasing rate packet train. The special train can efficiently avoid bias caused by multiple sampling and makes the tool converge fast. Analysis and simulations verify the effectiveness of the method under both the single-hop and multi-hop path with the bursty cross traffic environment, which also show that SLDRT estimates available bandwidth more, accurately and with less measurement overhead and intrusiveness than other existing techniques such as Pathload, pathChirp.