.....and in the best railway tradition, billions of £ overspent & delivered years late!
Indeed, the delays and the degree of overspending are most regrettable but are unfortunately the norm.
My concerns are not primarily the the cost and delays, but how reliable will the service be. Both initially and later when the whole route operates every day and more frequently.
Despite the thorough sounding test running, I have a slight fear that expectations regarding reliability will not survive contact with real passengers, including ill controlled children, giant baby carriages, oversized luggage, and those who are simply drunk or stupid.
Possible issues may include
Train doors, always a weak point as there are so many of them, and one fault fails the train. Hard to test properly during empty test running.
Signaling failures, high risk due to the greater complexity of modern systems.
Fire alarms being so sensitive that disruptive evacuations are frequent. "you cant have too much safety"
And of course on the above ground sections we have the normal hazards of wind, rain, snow, electrification failures, theft of cables, vandalism, and exploding pigeons. Such issues are of course not unique to Crossrail, but I feel that such a complex system may take a long while to recover from such.
I suspect that the "no toilets" policy will be regretted with soiling of trains and stations, especially in the late evening. I have no faith whatsoever in station toilets being reliably available.