The third era running to about 1910, saw longer (up to about 70 feet) wood cars, full vestibules, gas lighting and the modern floor plans for sleepers and other first class cars. It was the glory days for wood cars as they reached their zenith and also an era of great experimentation on the mechanical systems which made the cars livable. This era saw intensive work for example on heating and ventilation. This shows the observation car Yahk in Soo Line service in a 1923 photo on CPR tracks at Field, British Columbia.