The Beijing government has made massive investments in rail transit construction since the 2000s. While existing studies provide marginal values for rail access in the real estate market, little is known about homeowners’ happiness evaluation of such public investment. Using large-scale micro survey data, this paper estimates, in a difference-in-difference framework, the effects on homeowners’ happiness about public commuting and other residential realms of a transport improvement that altered the residence–station distance for some households, whilst leaving others unaffected. The estimation accounts for the endogeneity between the residential location choice and transport choice by using non-market (fang gai) housing with pre-determined residential location. It is found that better rail access not only provides sizeable happiness about public commuting to Beijing homeowners, but also affects their happiness in other residential realms. This finding adds to the evidence that public investment has an important role to play in influencing homeowners’ living experience.