I Believe that it was 2003, that Lionel did the Union Pacific Veranda Turbines (Not Diesels). Lionel also Produced the Late Union Pacific Challengers as well.
These are models to look at in regards to what Lionel can do in HO, both models were very well done, Highly Detailed, High Quality models.
In the Veranda Turbines Lionel did 2 Road #'s in each of the Grey and Silver trucks(both were correct)
Lionel went all out with the Challengers, they did 2 Road #'s in each of 6 versions 4 for the Union Pacific, Black/Coal Fired/ No Smoke Lifters, Black/Oil Fired/with Smoke Lifters. Two Tone Grey&Yellow/Oil Fired/with Smoke Lifters, Two Tone Grey&Silver(My Favorite)/Oil Fired/with Smoke Lifters
Plus they did 2 Road #'s for Rio Grande, and 2 Road #'s for the Clinchfield, which they even had separate tooling for the Clinchfield, and modeled them as modified by the Clinchfield, with a Single Stack, instead of the Dual stacks as used by the UP and Rio Grande.
Lionel produced these from Metal, and they were equipped with Full Dual Mode DC/DCC with Sound.
I have a complete collection of these models and have been very Happy with them, while I was still an active member of the Columbia Gorge Model Railroad Club in Portland, OR, these wer popular during our open house weekends in November, especially my 3980 TTG/Silver pulling a set of TTG/Silver Passenger cars. If you have seen the Disney STYLE childrens movie “Train Master” that was filmed at the CGMR, and my Passenger train makes a brief appearance.
I don’t know what Lionel’s HO plans are, but they are Very capable of “Getting it Right”, I would look more to the Challengers and Veranda Turbines, than the HO “Polar Express” as what to expect, the PE was designed and intended for a Childrens market, not the Avid Modeler.
Doug