changing trains in paris

Hi Mary, though you have adequate time for the transit between these two train stations, unfortunately there are no direct metro between the two. You need to change metro at Opera station, and with two suitcases up and down the many stairs..... The Paris metro is very short of escalators:-( We once did this trip but in reverse from Gare de l'Est to St. Lazare by taking bus 32. It worked perfectly well for us (this bus terminates at Gare de l'Est and passes by just in front of St. Lazare, but I believe you need to have metro/bus tickets in advance, as the bus driver doesn't issue tickets on the spot. The total travel time took no more than 20-25 mins. but again, it all depends on the traffic. We only travelled with trolleys, no suitcases. Travelling by bus in Paris, by the way, is a better than the metro, I believe. I can therefore only think of taxi as a last resort. Bon voyage!

Take the RER E between the two stations. According to the Paris transportation website, it's a 4 minute ride.
http://parisbytrain.com/

As Michael indicated, bus #32 goes directly between the stations. You CAN buy single tickets from the bus driver, but they are more expensive than those bought from a ticket machine. Alternatively, you can walk from Gare Saint-Lazare to the Haussmann - Saint-Lazare RER station, take the RER E one stop to the Magenta RER station (attached to the back end of Gare du Nord), walk through the tunnels to Gare du Nord, and take either metro line 4 or 5 one stop to Gare de l'Est. Or you can simply walk from Magenta to Gare de l'Est at street level (about ten minutes).

Mary, if it's raining and you prefer the Metro then try this. Take line 3 (direction Gallieni) to Réaumur Sébastopol (6 stops). Transfer to line 4 (direction Porte de Clignancourt to Gare de l'Est. (3 stops) Mike