Say Total 20 软卧车厢 in a train - Single Female customers go from 软卧车厢 No1 and then No2, etc. if she prefer 软卧车厢, while males/couples/family customers go from 软卧车厢 No20, then No19, etc. until all 软卧车厢 'sold out'. This way single females can separated from mixed and all/most 软卧车厢 will be sold out in most cases.
犯罪现象应该不常见,更多的是有些油腻男找搭讪艳遇,素质有比较差,让人不舒服