Sentence:  Under the former system, the convicts of Philadelphia were obliged to perform labor in the public streets under degrading circumstances. These prisoners were called " the <WSD>wheel-barrow men</WSD>," and were often exposed to insult and ill-treatment by the mob. 
Meaning of the word marked with <WSD> tags:  A convict sentenced to hard labor in the 1800s, especially one sentenced to work maintaining the roads.