On the stephenson-siemens game we are in 1996, and city roads are being downgraded to tarmac. I think the problem is in simuconf.tab, where the city_road-sma is set to be used before it is available. Either simuconf.tab should set 1997, or the intro of city_road-sma should be moved to 1996
simuconf.tab
city_road[3]=city_road,1933,1996
city_road[4]=city_road-sma,1996,2200
city-road.dat
Name=city_road
intro_year=1932
intro_month=1
retire_year=1996
retire_month=12
----
Name=city_road-sma
intro_year=1997
intro_month=1
Thank you for the report: now fixed.