We were already having drug dealers coming down from the Chicago suburbs in their cars, many of them associated with some gang or another. And they don't need train fare to access the unmanned Amtrak station in our town; anyone can enter it, ticketed or not, regardless of how they got there (although train fare might be cheaper than gas now!). Granted, I haven't seen the station defaced by grafitti yet, nor have I smelled pot there nor seen drug transactions taking place there personally (although I haven't had a family member catching the Lincoln Service trains from there in 3 1/2 years, so I've only driven past the station rather than parked there since then); however, we do still regularly read reports of local drug busts in the weekly newspaper, and it's usually the case that the drugs came into town from Chicago & its suburbs.
Good to hear that the Lincoln Service trains are already traveling at higher speeds, though!
Not to go too far off topic, but I think there are assumed characteristics of drug use at play here. According to NIH studies, there isn't much significant difference in the use of recreational drugs between urban and rural areas, although there are more recreational drug overdose deaths in urban areas. Likewise, abuse of opioids is now widespread but was certainly a rural issue at the start. To put it mildly, drug sales only happen because someone wants to buy.
Drug busts also only capture drugs for sale where the drug busts are taking place. For example, I live on the north side of Chicago, in a predominantly white neighborhood. I know numerous people who have purchased and used cocaine. They do so with virtually no fear of legal consequences. People smoke marijuana in public with no fear of anything. Even before it was legalized, I have witnessed people in a public park smoking marijuana and a police officer literally walk right past them (not that I felt they should be arrested). At the bars and clubs in River North, it is an accepted fact that (wealthy) people are using "designer drugs" - stimulants, methamphetamines, etc.
To put it simply, there are no drug busts where I live. The police aren't raiding the clubs. No one seems to care. Ten miles to the south, on the south side of Chicago, drug busts are a fact of everyday life.
As for the Lincoln Service - one person's anecdotal examples only add up to so much, but for me personally, I've had a lot more problems with passengers boarding "downstate" than originating from Chicago, Summit or Joliet. Once, a woman who was clearly a ticket dodger tried to steal my phone (long story, but I lent it to her to make a phone call, she showed no signs of giving it back, tried to switch to the aisle seat from the window right before a station stop. I could put 2 and 2 together). I've also had intoxicated and fairly belligerent people in my car who boarded downstate headed toward STL, on more than one occasion.
Again, no anecdotal example is representative of the whole.