It is all too easy to blame the railway authorities when something does go wrong.

It is all too easy to blame the railway authorities when something does go wrong.

在一般情况下，too . . .to do 结构具有否定意义。
但是，当all too , but too , only too , quite too 与动词不定式连用时，就没有否定意义了。
It is all too easy to blame the railway authorities when something does go wrong.  
当事情出错时，很容易责怪铁路当局。 
类似例句：
They are but too glad to do so.

他们很高兴这样做。