Trenes Especiales Argentinos (TEA) offers train service from Buenos Aires to Posadas scheduled to take 26 hours which turned to 28 hours with delays. The schedule departs from Buenos Aires to Posadas on Tuesdays and Fridays at 10:50am and return from Posadas to Buenos Aires Wednesdays and Sundays at 7pm.
We booked a sleeper compartment for ARP150 per person. No reservations are taken over the phone. However, my partner arranged to find someone fluent in Spanish to call from Alaska, the person on the phone was so impressed she made an exception to reserve a sleeper compartment. You may reach the Lacroze Train Station via Subte or Colectivos (public buses) to Federico Lacroze station.
Bring enough cash for train ticket purchase, no credit cards, no ATM at the train station.
There are restaurants and food places directly across the street from the train station entrance along Av. Corrientes over into the next block to Olleros should you wish to stock up with food and or drinks as we did. Wear dark shoes or boots as we head towards Posadas, the soil is rich in oxidized iron accounting for the bright red soil, and tainted my shoes with red dirt. No towels or soap are provided, pack along a face or hand towel and soap bar to clean yourself, no shower facility, don't expect toilet paper to be available, air-conditioning went out part of the time, electrical lighting was erratic, there is a covered sink with a foot activated valve in the sleeper. There's no dining car, but a cafeteria with very limited food service. The staff offered a ham and cheese or breaded beef sandwich. The breaded beef sandwich was quite tasty.
Despite all these inconveniences, the experience provided us an opportunity to interact with other passengers, staff, and others along the way through this short journey that we would not otherwise would have done.
We learn to appreciate for what we have, to learn to be a little kinder to one another. I found myself to like the woman with her baby and husband in the next compartment, observing her love for her little baby with unconditional, genuine love, attention even though we didn't speak the same language, and even waved to each other and smiling one last time as we were being whisked away in our taxi. It wasn't a particularly comfortable experience but a rather emotionally enriching satisfying travel experience despite the lack of modern creature comforts.