Note the third rail in that photo. The Guatemalan railroad (now defunct) was narrow gage... The photo is most likely at Mexico’s southern border where railroads interchanged.
I once rode all the way through Mexico and Guatemala by rail... it was not very glamourous... from Juarez to Mexico City, to Vera Cruz, to Tapachula, to Ciudad Hildalgo... walking across the border to Tecun Uman and taking the narrow gage train to Guatemala City. My total passenger train fare was about $30, if I recall correctly.
I did ride the roof in Guatemala... but that was normal... they still had brakemen riding the tops of the cars with brake clubs tucked under their armpit for cranking down the handbrakes.
Amazing!