GIBSONIA — There’s a difference between a tin plater and a railroad modeler.

A tin plater is slang for someone who is content to set up a Lionel train to run on a circular track around a Christmas tree base.

A railroad modeler will build a 40-by-100-foot train layout for up to 24 HO-scale trains and keep it set up all year round in a building erected specifically for the layout.

That’s what the Western Pennsylvania Model Railroad Museum, 5507 Lakeside Drive, has on the second floor of its building, an intricate and meticulously created combination of tracks, trains, buildings, vegetation and animals forming cityscapes and countrysides that recreate the area between the Point in Pittsburgh and Cumberland, Md.

HO scale means model trains of this type use a 1:87 scale in relation to a full-sized train, and the museum modelers do their best to keep their buildings, streets, factories and landscapes in the same scale.

Visitors can see this detailed landscape for themselves as the museum has opened its doors to the public for its 34th Holiday Train Display.

During the display, the museum is open from 6 to 9 p.m. Fridays and from 11 a.m. to 5 p.m. Saturdays and Sundays, with the museum closed on Dec. 24 and 25 and New Year’s Day. There are special holiday hours from 11 a.m. to 5 p.m. Dec. 26 to 29, 11 a.m. to 9 p.m. Dec. 30, and 11 a.m. to 5 p.m. Dec. 31. There are also some hours in January.

The all-volunteer 501(c)(3) organization suggests a $10 admission for adults and $5 for children younger than 12.

The first floor of the museum contains a gift shop, snack bar, walls covered with railroad pictures and advertisements, an N-gauge train that runs along a track close to the ceiling, and several hands-on train displays for the younger visitors.

Upstairs is what museum vice president Bill Humphrey calls a “freelance reality.”

“The real world is huge, and this is a 65% percent full-size replica complete with trolleys running on the Smithfield Street Bridge, ” said Humphrey. “It’s very, very realistic to the point where people who see it can say, ‘That’s my house.’ That’s the kind of accuracy we get.”

The surroundings are built to be in scale with the HO scale or 1/87th life-size scale of the trains that run on the display.

If it were real life, the display would be two-thirds of a mile wide and 113 miles long to show the train tracks traveling through Pittsburgh to McKeesport to Connellsville and Rockwood and on south to Cumberland.

The museum chose to depict the period of the late 1940s to mid-1950s because the railroads were switching from steam engines to electric engines thus allowing it to feature both models on the trains running through the display.

As visitors walk around, watching as lights in houses and factories wink on when it suddenly becomes “night,” they are always looking “north.”

He said the museum’s display is one of only five like it in the country.

Keeping track of the 24 trains on a recent Saturday were Mark Sparrow and Dave Takus manning the “dispatch office, ” a room where they watched computer screens keeping track of the location and speed of each train throughout the sprawling display.

Takus, a 30-year member of the museum, said, “Sensors on the track are broken into sections called blocks. The block reports to the computer.”

Sparrow, who’s been a member for 13 years, said it takes a train about 15 minutes to travel through the whole display. He said the trains are controlled by a desktop computer.

The most common mishaps are a train derailment or a train will stall or decouple from its cars, Sparrow added.

Takus said, “Thirty years ago, the biggest sea change came when they started putting computers in the locomotive.”

“For me the appeal was in the miniaturization, the electronics, the laying of tracks and doing scenery,” said Takus.

He said the train tracks on the display do not take a lot of maintenance. “But,” he added, “there is tons of crazy wiring for the computer interface underneath.”

The museum’s 90 members do all the chores around the museum from snow removal to cutting the grass. That’s time, according to Humphrey, that they would rather be using building hillsides, the houses of the towns the tracks pass by, and more city scenes.

Humphrey said the museum’s members create the scenery and buildings by carefully crafting components from wood and plastic and even using the museum’s 3D printer.

“Downstairs becomes the workshop for most the year. We’re working on the details of the next project. There’s way too much to take this stuff down,” he said.

Humphrey said, “We have to do historical research, learning how real railroads do things so we can replicate it.”

John Emph, a 16-year member of the museum, said, “I started out doing modeling, building buildings, and then I started running the trains. Then I became treasurer and spent time on the books. I just stepped back from that.”

Ten-year member George Richard said the project he was working recently was building a J&L steel mill in the Glenwood section the display. He had previously constructed an ice house and a roundhouse.

“It had three blast furnaces. I have to put that together and all the track. It will be just as it was,” he said.

Richard said, “We get as much as we can from old photos, diagrams and blueprints. We got a general idea for the roundhouse from old photos.”

Humphrey said the museum, in existence since 1938, has been working on this display since it built its present headquarters in 1986 following a master plan.

“It’s only open at this time of year,” said Humphrey. “The rest of the year we’re busy working on updates, cleaning everywhere in the building and changing all the lights to LEDs.”

When not working on the massive display or answering visitors’ questions, the museum members spend time sorting through everything that people have donated. That includes old train sets, books, posters and pictures.

Humphrey pointed to one train set displayed on the wall: a pink steam locomotive with a blue caboose.

“If that would have been in its original box, it would be worth $25,000 to $30,000,” said Humphrey. “It was made in 1949 to get girls interested in playing with trains. Lionel only made a limited number of them.”

Lionel’s attempt to get girls interested in trains may have faltered, but Humphrey had a simple explanation for trains’ continuing appeal to boys.

“Anything that moves, that’s big and dirty and makes a lot of noise, isn’t that every boy’s fantasy?” he asked.