Help identify MTH passenger cars

Hello all,
I bought a group of trains at an estate sale. In the sale was included a 4 car passenger set only in the styrofoam inserts. There are two inserts that hold two cars each. The cars are streamlined ribbed Southern Pacific Daylight cars, 3300 Baggage, 2354 coach, offset vista dome “San Francisco, and an observation 2950. The cars are 17” long from coupler to coupler, labeled MTH Electric Trains on the bottom and the trucks have MTH embossed on them. I have been to the MTH website with no luck. They look to have never been run, besides a little dust seem flawless, I am sure they are factory. I have some knowledge of o gauge trains as I have collected them most of my life, but I have looked these up online and can not find any information on them. I am assuming they are a four car set because of the inserts, they are larger than the Railking cars. I just can’t even find one of these cars on EBay or online. Any help with a model number would be helpful or a link to where I can find information on them.

Thank you

Here is a picture of the cars.