This applicant is by far the better than that one.
可以肯定地说，这个句子是个错句。《剑桥英语语法》（the Cambridge Grammar of the English Language）在p 1132 讨论比较级前的the的使用时明确指出：
The is completely excluded if the secondary term is expressed: *The result is the better than I expected. Nor is the permitted when the secondary term is recoverable anaphorically, from what has gone before. We cannot, for example, insert the in It was cloudy and cold for the first two days but on the third day the weather was better, where we understand "better than on the first two days".
即一旦有than分句出现表示比较对象，比较级前的定冠词是完全不能使用的（completely excluded）。
所以，这个句子可作如下修改：
This applicant is far better than that one.
This applicant is by far the better of the two.
一般认为by far通常强调最高级，词典例句也多为by far后接最高级的例句。但 COCA语料库有不少 by far the +比较级的例句，说明至少这种用法在美式英语非正式语体是可能使用的。
2 It is by far the quicker to go by train.
这个句子应该是没有问题的。句子等于 To go by train is by far the quicker of the two means.
